Mobile communication system

ABSTRACT

In a mobile communication system according to the present invention, with the separate use of a plurality of component carriers or with the use of a carrier set including the plurality of component carriers aggregated, a base station performs radio communication with a user equipment corresponding to the component carrier or a user equipment corresponding to the aggregated carriers. In particular, in a case where the base station performs radio communication with the user equipment corresponding to the aggregated carriers with the use of the aggregated carriers, each of a plurality of transport blocks created by dividing a transport channel is transmitted per each of the plurality of component carriers constituting the aggregated carriers, and control information related to radio communication between the base station and the user equipment corresponding to the aggregated carriers is transmitted such that physical information of the corresponding component carrier is identifiable. Accordingly, communication control is performed efficiently while improving a communication speed correspondingly to the aggregated carriers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of U.S. application Ser. No.15/164,586, filed on May 25, 2016, which is a divisional of U.S.application Ser. No. 14/531,516, filed on Nov. 3, 2014 (now U.S. Pat.No. 9,386,577), which is a divisional of U.S. application Ser. No.13/378,380, filed on Dec. 15, 2011 (now U.S. Pat. No. 8,908,560), whichis a U.S. national phase application of International ApplicationPCT/JP2010/003969, filed on Jun. 15, 2010, and claims the benefit ofpriority from Japanese Application No. 2009-146295, filed on Jun. 19,2009, and Japanese Application No. 2010-086195, filed on Apr. 2, 2010.The entire contents of each of which are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to a mobile communication system in whicha base station performs radio communication with a plurality of userequipments.

BACKGROUND ART

Commercial service of a wideband code division multiple access (W-CDMA)system among so-called third-generation communication systems has beenoffered in Japan since 2001. In addition, high speed down link packetaccess (HSDPA) service for achieving higher-speed data transmissionusing a down link has been offered by adding a channel for packettransmission high speed-downlink shared channel (HS-DSCH)) to the downlink (dedicated data channel, dedicated control channel). Further, inorder to increase the speed of data transmission in an uplink direction,service of a high speed up link packet access (HSUPA) has been offered.W-CDMA is a communication system defined by the 3rd generationpartnership project (3GPP) that is the standard organization regardingthe mobile communication system, where the specifications of Release 8version are produced.

Further, 3GPP is studying new communication systems referred to as “longterm evolution (LTE)” regarding radio areas and “system architectureevolution (SAE)” regarding the overall system configuration including acore network (merely referred to as network as well) as communicationsystems independent of W-CDMA. In the LTE, an access scheme, radiochannel configuration and a protocol are totally different from those ofthe current W-CDMA (HSDPA/HSUPA). For example, as to the access scheme,code division multiple access is used in the W-CDMA, whereas in the LTE,orthogonal frequency division multiplexing (OFDM) is used in a downlinkdirection and single career frequency division multiple access (SC-FDMA)is used in an uplink direction. In addition, the bandwidth is 5 MHz inthe W-CDMA, while in the LTE, the bandwidth can be selected from 1.4MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz and 20 MHz for each base station.Further, differently from the W-CDMA, circuit switching is not providedbut a packet communication system is only provided in the LTE.

The LTE is defined as a radio access network independent of the W-CDMAnetwork because its communication system is configured with a new corenetwork different from a core network (GPRS) of the W-CDMA. Therefore,for differentiation from the W-CDMA communication system, a base stationthat communicates with a user equipment (UE) and a radio networkcontroller that transmits/receives control data and user data to/from aplurality of base stations are referred to as an E-UTRAN NodeB (eNB) andan evolved packet core (EPC: also referred to as access gateway (aGW)),respectively, in the LTE communication system. Unicast service andevolved multimedia broadcast multicast service (E-MBMS service) areprovided in this LTE communication system. The E-MBMS service isbroadcast multimedia service, which is merely referred to as MBMS insome cases. Bulk broadcast contents such as news, weather forecast andmobile broadcast are transmitted to a plurality of UEs. This is alsoreferred to as point to multipoint service.

Non-Patent Document 1 describes the current decisions by 3GPP regardingan overall architecture in the LTE system. The overall architecture(Chapter 4 of Non-Patent Document 1) is described with reference to FIG.1 . FIG. 1 is a diagram illustrating the configuration of the LTEcommunication system. With reference to FIG. 1 , the evolved universalterrestrial radio access (E-UTRAN) is composed of one or a plurality ofbase stations 102, provided that a control protocol (for example, radioresource management (RRC)) and a user plane (for example, packet dataconvergence protocol (PDCP), radio link control (RLC), medium accesscontrol (MAC), and physical layer (PHY)) for a UE 101 are terminated inthe base station 102. The base stations 102 perform scheduling andtransmission of paging signaling (also referred to as paging messages)notified from a mobility management entity (MME) 103. The base stations102 are connected to each other by means of an X2 interface. Inaddition, the base stations 102 are connected to an evolved packet core(EPC) by means of an S1 interface, more specifically, connected to themobility management entity (MME) 103 by means of an S1_MME interface andconnected to a serving gateway (S-GW) 104 by means of an S1_U interface.The MME 103 distributes the paging signaling to multiple or a singlebase station 102. In addition, the MME 103 performs mobility control ofan idle state. When the UE is in the idle state and an active state, theMME 103 manages a list of tracking areas. The S-GW 104transmits/receives user data to/from one or a plurality of base stations102. The S-GW 104 serves as a local mobility anchor point in handoverbetween base stations. Moreover, there is provided a PDN gateway (P-GW),which performs per-user packet filtering and UE-ID address allocation.

The control protocol RRC between the UE 101 and the base station 102performs broadcast, paging, RRC connection management and the like.

The states of the base station and the UE in RRC are classified intoRRC_Idle and RRC_CONNECTED.

In RRC_IDLE, public land mobile network (PLMN) selection, systeminformation (SI) broadcast, paging, cell re-selection, mobility and thelike are performed.

In RRC_CONNECTED, the UE has RRC connection, is capable oftransmitting/receiving data to/from a network, and performs, forexample, handover (HO) and measurement of a neighbor cell.

The current decisions by 3GPP regarding the frame configuration in theLTE system are described in Non-Patent Document 1 (Chapter 5), which aredescribed with reference to FIG. 2 . FIG. 2 is a diagram illustratingthe configuration of a radio frame used in the LTE communication system.With reference to FIG. 2 , one radio frame is 10 ms. The radio frame isdivided into ten equally sized sub-frames. The subframe is divided intotwo equally sized slots. The first and sixth subframes contain adownlink synchronization signal (SS) per each radio frame. Thesynchronization signals are classified into a primary synchronizationsignal (P-SS) and a secondary synchronization signal (S-SS).Multiplexing of channels for multimedia broadcast multicast servicesingle frequency network (MBSFN) and for non-MBSFN is performed on aper-subframe basis. Hereinafter, a subframe for MBSFN transmission isreferred to as an MBSFN sub-frame. Non-Patent Document 2 describes asignaling example when MBSFN subframes are allocated. FIG. 3 is adiagram illustrating the configuration of the MBSFN frame. Withreference to FIG. 3 , the MBSFN subframes are allocated for each MBSFNframe. An MBSFN frame cluster is scheduled. A repetition period of theMBSFN frame cluster is allocated.

Non-Patent Document 1 describes the current decisions by 3GPP regardingthe channel configuration in the LTE system. It is assumed that the samechannel configuration is used in a closed subscriber group (CSG) cell asthat of a non-CSG cell. A physical channel (Chapter 5 of Non-PatentDocument 1) is described with reference to FIG. 4 . FIG. 4 is a diagramillustrating physical channels used in the LTE communication system.With reference to FIG. 4 , a physical broadcast channel 401 (PBCH) is adownlink channel transmitted from the base station 102 to the UE 101. ABCH transport block is mapped to four subframes within a 40 ms interval.There is no explicit signaling indicating 40 ms timing. A physicalcontrol format indicator channel 402 (PCFICH) is transmitted from thebase station 102 to the UE 101. The PCFICH notifies the number of OFDMsymbols used for PDCCHs from the base station 102 to the UE 101. ThePCFICH is transmitted in each subframe. A physical downlink controlchannel 403 (PDCCH) is a downlink channel transmitted from the basestation 102 to the UE 101. The PDCCH notifies the resource allocation,HARQ information related to DL-SCH (downlink shared channel that is oneof the transport channels shown in FIG. 5 ) and the PCH (paging channelthat is one of the transport channels shown in FIG. 5 ). The PDCCHcarries an uplink scheduling grant. The PDCCH carries ACK/Nack that is aresponse signal to uplink transmission. The PDCCH is referred to as anL1/L2 control signal as well. A physical downlink shared channel 404(PDSCH) is a downlink channel transmitted from the base station 102 tothe UE 101. A DL-SCH (downlink shared channel) that is a transportchannel and a PCH that is a transport channel are mapped to the PDSCH. Aphysical multicast channel 405 (PMCH) is a downlink channel transmittedfrom the base station 102 to the UE 101. A multicast channel (MCH) thatis a transport channel is mapped to the PMCH.

A physical uplink control channel 406 (PUCCH) is an uplink channeltransmitted from the UE 101 to the base station 102. The PUCCH carriesACK/Nack that is a response signal to downlink transmission. The PUCCHcarries a channel quality indicator (CQI) report. The CQI is qualityinformation indicating the quality of received data or channel quality.In addition, the PUCCH carries a scheduling request (SR). A physicaluplink shared channel 407 (PUSCH) is an uplink channel transmitted fromthe UE 101 to the base station 102. A UL-SCH (uplink shared channel thatis one of the transport channels shown in FIG. 5 ) is mapped to thePUSCH. A physical hybrid ARQ indicator channel 408 (PHICH) is a downlinkchannel transmitted from the base station 102 to the UE 101. The PHICHcarries ACK/Nack that is a response to uplink transmission. A physicalrandom access channel 409 (PRACH) is an uplink channel transmitted fromthe UE 101 to the base station 102. The PRACH carries a random accesspreamble.

A downlink reference signal which is a known symbol in a mobilecommunication system is inserted in the first, third and last OFDMsymbols of each slot. The physical layer measurement objects of a UEinclude, for example, reference symbol received power (RSRP).

The transport channel (Chapter 5 of Non-Patent Document 1) is describedwith reference to FIG. 5 . FIG. 5 is a diagram illustrating transportchannels used in the LTE communication system. FIG. 5A shows mappingbetween a downlink transport channel and a downlink physical channel.FIG. 5B shows mapping between an uplink transport channel and an uplinkphysical channel. A broadcast channel (BCH) is broadcast to the entirebase station (cell) regarding the downlink transport channel. The BCH ismapped to the physical broadcast channel (PBCH). Retransmission controlaccording to a hybrid ARQ (HARQ) is applied to a downlink shared channel(DL-SCH). Broadcast to the entire base station (cell) is enabled. TheDL-SCH supports dynamic or semi-static resource allocation. Thesemi-static resource allocation is also referred to as persistentscheduling. The DL-SCH supports discontinuous reception (DRX) of a UEfor enabling the UE to save power. The DL-SCH is mapped to the physicaldownlink shared channel (PDSCH). The paging channel (PCH) supports DRXof the UE for enabling the UE to save power. Broadcast to the entirebase station (cell) is required. The PCH is mapped to physical resourcessuch as the physical downlink shared channel (PDSCH) that can be useddynamically for traffic or physical resources such as the physicaldownlink control channel (PDCCH) of the other control channel. Themulticast channel (MCH) is used for broadcast to the entire base station(cell). The MCH supports SFN combining of MBMS service (MTCH and MCCH)in multi-cell transmission. The MCH supports semi-static resourceallocation. The MCH is mapped to the PMCH.

Retransmission control according to a hybrid ARQ (HARQ) is applied to anuplink shared channel (UL-SCH). The UL-SCH supports dynamic orsemi-static resource allocation. The UL-SCH is mapped to the physicaluplink shared channel (PUSCH). A random access channel (RACH) shown inFIG. 5B is limited to control information. There is a collision risk.The RACH is mapped to the physical random access channel (PRACH). TheHARQ is described.

The HARQ is the technique for improving the communication quality of achannel by combination of automatic repeat request and forward errorcorrection. The HARQ has an advantage that error correction functionseffectively by retransmission even for a channel whose communicationquality changes. In particular, it is also possible to achieve furtherquality improvement in retransmission through combination of thereception results of the first transmission and the reception results ofthe retransmission. An example of the retransmission method isdescribed. In a case where the receiver fails to successfully decode thereceived data (in a case where a cyclic redundancy check (CRC) erroroccurs (CRC=NG)), the receiver transmits “Nack” to the transmitter. Thetransmitter that has received “Nack” retransmits the data. In a casewhere the receiver successfully decodes the received data (in a casewhere a CRC error does not occur (CRC=OK)), the receiver transmits “AcK”to the transmitter. The transmitter that has received “Ack” transmitsthe next data. Examples of the HARQ system include “chase combining”. Inchase combining, the same data sequence is transmitted in the firsttransmission and retransmission, which is the system for improving gainsby combining the data sequence of the first transmission and the datasequence of the retransmission in retransmission. This is based on theidea that correct data is partially included even if the data of thefirst transmission contains an error, and highly accurate datatransmission is enabled by combining the correct portions of the firsttransmission data and the retransmission data. Another example of theHARQ system is incremental redundancy (IR). The IR is aimed to increaseredundancy, where a parity bit is transmitted in retransmission toincrease the redundancy by combining the first transmission andretransmission, to thereby improve the quality by an error correctionfunction.

A logical channel (Chapter 6 of Non-Patent Document 1) is described withreference to FIG. 6 . FIG. 6 is a diagram illustrating logical channelsused in an LTE communication system. FIG. 6A shows mapping between adownlink logical channel and a downlink transport channel. FIG. 6B showsmapping between an uplink logical channel and an uplink transportchannel. A broadcast control channel (BCCH) is a downlink channel forbroadcast system control information. The BCCH that is a logical channelis mapped to the broadcast channel (BCH) or downlink shared channel(DL-SCH) that is a transport channel. A paging control channel (PCCH) isa downlink channel for transmitting paging signals. The PCCH is usedwhen the network does not know the cell location of a UE. The PCCH thatis a logical channel is mapped to the paging channel (PCH) that is atransport channel. A common control channel (CCCH) is a channel fortransmission control information between UEs and a base station. TheCCCH is used in a case where the UEs have no RRC connection with thenetwork. In downlink, the CCCH is mapped to the downlink shared channel(DL-SCH) that is a transport channel. In uplink, the CCCH is mapped tothe UL-SCH that is a transport channel.

A multicast control channel (MCCH) is a downlink channel forpoint-to-multipoint transmission. The MCCH is a channel used fortransmission of MBMS control information for one or several MTCHs from anetwork to a UE. The MCCH is a channel used only by a UE duringreception of the MBMS. The MCCH is mapped to the downlink shared channel(DL-SCH) or multicast channel (MCH) that is a transport channel. Adedicated control channel (DCCH) is a channel that transmits dedicatedcontrol information between a UE and a network. The DCCH is mapped tothe uplink shared channel (UL-SCH) in uplink and mapped to the downlinkshared channel (DL-SCH) in downlink. A dedicate traffic channel (DTCH)is a point-to-point communication channel for transmission of userinformation to a dedicated UE. The DTCH exists in uplink as well asdownlink. The DTCH is mapped to the uplink shared channel (UL-SCH) inuplink and mapped to the downlink shared channel (DL-SCH) in downlink. Amulticast traffic channel (MTCH) is a downlink channel for traffic datatransmission from a network to a UE. The MTCH is a channel used only bya UE during reception of the MBMS. The MTCH is mapped to the downlinkshared channel (DL-SCH) or multicast channel (MCH).

GCI represents a global cell identity. A closed subscriber group (CSG)cell is introduced in the LTE and universal mobile telecommunicationsystem (UMTS). The CSG is described below (Chapter 3.1 of Non-PatentDocument 4). The closed subscriber group (CSG) is a cell in whichsubscribers who are permitted to use are identified by an operator (cellfor identified subscribers). The identified subscribers are permitted toaccess one or more E-UTRAN cells of a public land mobile network (PLMN).One or more E-UTRAN cells in which the identified subscribers arepermitted to access are referred to as “CSG cell(s)”. Note that accessis limited in the PLMN. The CSG cell is part of the PLMN that broadcastsa specific CSG identity (CSG ID, CSG-ID). The authorized members of thesubscriber group who have registered in advance access the CSG cellsusing the CSG-ID that is the access permission information. The CSG-IDis broadcast by the CSG cell or cells. A plurality of CSG-IDs exist in amobile communication system. The CSG-IDs are used by UEs for makingaccess from CSG-related members easier. 3GPP discusses in a meeting thatthe information to be broadcast by the CSG cell or cells is changed fromthe CSG-ID to a tracking area code (TAC). The locations of UEs aretraced based on an area composed of one or more cells. The locations aretraced for enabling tracing of the locations of UEs and calling (callingof UEs) even in an idle state. An area for tracing locations of UEs isreferred to as a tracking area. A CSG whitelist is a list stored in theUSIM containing all the CSG IDs of the CSG cells to which thesubscribers belong. The whitelist of the UE is provided by a higherlayer. By means of this, the base station of the CSG cell allocatesradio resources to the UEs.

A “suitable cell” is described below (Chapter 4. 3 of Non-PatentDocument 4). The “suitable cell” is a cell on which a UE camps to obtainnormal service. Such a cell shall fulfill the following: (1) the cell ispart of the selected PLMN or the registered PLMN, or part of the PLMN ofan “equivalent PLMN list”; and (2) according to the latest informationprovided by a non-access stratum (NAS), the cell shall further fulfillthe following conditions: (a) the cell is not a barred cell; (b) thecell is part of at least one tracking area (TA), not part of “forbiddenLAs for roaming”, where the cell needs to fulfill (1) above; (c) thecell shall fulfill the cell selection criteria; and (d) for a cellidentified as CSG cell by system information (SI), the CSG-ID is part ofa “CSG whitelist” of the UE (contained in the CSG whitelist of the UE).

An “acceptable cell” is described below (Chapter 4.3 of Non-PatentDocument 4). This is the cell on which a UE camps to obtain limitedservice (emergency calls). Such a cell shall fulfill all the followingrequirements. That is, the minimum required set for initiating anemergency call in an E-UTRAN network are as follows: (1) the cell is nota barred cell; and (2) the cell fulfills the cell selection criteria.

Camping on a cell represents the state where a UE has completed the cellselection/reselection process and the UE has chosen a cell formonitoring the system information and paging information.

3GPP is studying base stations referred to as Home-NodeB (Home-NB, HNB)and Home-eNodeB (Home-eNB, HeNB). HNB/HeNB is a base station for, forexample, household, corporation or commercial access service inUTRAN/E-UTRAN. Non-Patent Document 6 discloses three different modes ofthe access to the HeNB and HNB. Those are an open access mode, a closedaccess mode and a hybrid access mode. The respective modes have thefollowing characteristics. In the open access mode, the HeNB and HNB areoperated as a normal cell of a normal operator. In the closed accessmode, the HeNB and HNB are operated as a CSG cell. The CSG cell is acell where only CSG members are allowed access. In the hybrid accessmode, the HeNB and HNB are CSG cells where non-CSG members are allowedaccess at the same time. In other words, a cell in the hybrid accessmode is the cell that supports both the open access mode and the closedaccess mode.

PRIOR ART DOCUMENTS Non-Patent Documents

-   Non-Patent Document 1: 3GPP TS36.300 V8.6.0 Chapter 4, 5 and 6-   Non-Patent Document 2: 3GPP R1-072963-   Non-Patent Document 3: TR R3.020 V0.6.0-   Non-Patent Document 4: 3GPP TS36.304 V8.4.0 Chapter 3.1, Chapter    4.3, Chapter 5.2.4.2, Chapter 5.2.4.3, Chapter 5.2.4.6, Chapter 7.1    and Chapter 7.2-   Non-Patent Document 5: 3GPP R2-082899-   Non-Patent Document 6: 3GPP S1-083461-   Non-Patent Document 7: TR 36.814 V1.0.0 Chapter 5-   Non-Patent Document 8: 3GPP R1-090860-   Non-Patent Document 9: 3GPP TS36.331 V8.5.0 Chapter 6.2.2 and    Chapter 6.3.2-   Non-Patent Document 10: 3GPP R2-093104-   Non-Patent Document 11: 3GPP R2-092180-   Non-Patent Document 12: 3GPP R2-093204-   Non-Patent Document 13: TS36.321 V8.5.0-   Non-Patent Document 14: R2-100812-   Non-Patent Document 15: TS36.331 V9.1.0-   Non-Patent Document 16: TR36.912 V9.1.0-   Non-Patent Document 17: R2-101423-   Non-Patent Document 18: R2-100531

SUMMARY OF INVENTION Problem to be Solved by the Invention

In the long term evolution advanced (LTE-A) system, it is consideredthat a frequency bandwidth larger than the frequency bandwidth of theLTE system is supported. This is for improving a communication speed.Currently, 3GPP is discussing that the frequency bandwidth of the LTE-Asystem is equal to or smaller than 100 MHz.

Frequency usage situation varies from area to area. Therefore, it isconceivable that there is an area in which 100 MHz cannot be securedcontinuously for the frequency bandwidth. In addition, a compatibleoperation of an LTE-compliant UE is taken into account in the LTE-Asystem. Along with this, currently, 3GPP considers division of thefrequency band (carrier) in units referred to as component carriers.3GPP now aims to make an LTE-compliant UE to be operable on thecomponent carrier. Further, it is intended to achieve an improvement incommunication speed as an LTE-A system with the use of the aggregatedcarriers created by aggregating component carriers.

An object of the present invention is to provide a mobile communicationsystem capable of efficiently controlling communication while achievingan improvement in communication speed correspondingly to aggregatedcarriers.

Means to Solve the Problem

The present invention relates to a mobile communication system in which,with the separate use of a plurality of component carriers or with theuse of aggregated carriers including the plurality of component carriersaggregated, a base station performs radio communication with a userequipment corresponding to the component carrier or a user equipmentcorresponding to the aggregated carriers, wherein in a case where thebase station performs radio communication with the user equipmentcorresponding to the aggregated carriers with the use of the aggregatedcarriers, each of a plurality of transport blocks created by dividing atransport channel is transmitted per each of the plurality of componentcarriers constituting the aggregated carriers, and control informationrelated to radio communication between the base station and the userequipment corresponding to the aggregated carriers is transmitted sothat physical information of the corresponding component carrier isidentifiable.

Effects of the Invention

According to the present invention, the control information related toradio communication between the base station and the user equipmentcorresponding to the aggregated carriers is transmitted so that physicalinformation of the corresponding component carrier is identifiable,whereby it is possible to perform efficient communication control.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating the configuration of an LTEcommunication system. FIG. 1 is a diagram illustrating the configurationof an LTE communication system.

FIG. 2 is a diagram illustrating the configuration of a radio frame usedin the LTE communication system.

FIG. 3 is a diagram illustrating the configuration of a multimediabroadcast multicast service single frequency network (MBSFN) frame.

FIG. 4 is a diagram illustrating physical channels used in the LTEcommunication system.

FIG. 5 is a diagram illustrating transport channels used in the LTEcommunication system.

FIG. 6 is a diagram illustrating logical channels used in the LTEcommunication system.

FIG. 7 is a block diagram showing the overall configuration of a mobilecommunication system currently under discussion of 3GPP.

FIG. 8 is a block diagram showing the configuration of a user equipment311 according to the present invention.

FIG. 9 is a block diagram showing the configuration of a base station312 according to the present invention.

FIG. 10 is a block diagram showing the configuration of an MME accordingto the present invention.

FIG. 11 is a block diagram showing the configuration of a HeNBGWaccording to the present invention.

FIG. 12 is a flowchart showing an outline of cell search performed by auser equipment (UE) in the LTE communication system.

FIG. 13 is a diagram showing a downlink layer 2 structure for carrieraggregation, which is currently under discussion of 3GPP.

FIG. 14 is a diagram showing an uplink layer 2 structure for carrieraggregation, which is currently under discussion of 3GPP.

FIG. 15 is a diagram illustrating a first specific example of theinformation indicating the control information corresponding to whatcomponent in a third solution according to a first embodiment.

FIG. 16 is a diagram illustrating a second specific example of theinformation indicating the control information corresponding to whatcomponent in the third solution according to the first embodiment.

FIG. 17 is a diagram illustrating a third specific example of theinformation indicating the control information corresponding to whatcomponent in the third solution according to the first embodiment.

FIG. 18 is a diagram illustrating a specific example of numbering ofidentifiers of components in the third solution according to the firstembodiment.

FIG. 19 is a sequence diagram showing the operation of a mobilecommunication system in the third solution according to the firstembodiment.

FIG. 20 is a sequence diagram showing the operation of a mobilecommunication system in a third solution according to a secondembodiment.

FIG. 21 is a diagram showing a downlink layer 2 structure for carrieraggregation, which is disclosed in a first modification of the secondembodiment.

FIG. 22 is a diagram showing an uplink layer 2 structure for carrieraggregation, which is disclosed in the first modification of the secondembodiment.

FIG. 23 is a diagram illustrating a first specific example of theinformation indicating scheduling components in a second solutionaccording to a third embodiment.

FIG. 24 is a diagram illustrating a second specific example of theinformation indicating the scheduling components in the second solutionaccording to the third embodiment.

FIG. 25 is a diagram illustrating a third specific example of theinformation indicating the scheduling components in the second solutionaccording to the third embodiment.

FIG. 26 is a conceptual diagram showing association of component indicesand scheduling components, which is performed in a component schedulingblock in the second solution according to the third embodiment.

FIG. 27 is a sequence diagram showing the operation of a mobilecommunication system in the second solution according to the thirdembodiment.

FIG. 28 is a conceptual diagram showing a solution according to a fourthembodiment.

FIG. 29 is a sequence diagram showing the operation of a mobilecommunication system in the solution according to the fourth embodiment.

FIG. 30 is a sequence diagram showing the operation of a mobilecommunication system in a solution according to a first modification ofthe fourth embodiment.

FIG. 31 is a conceptual diagram in a case where comparison is madebetween a set component carrier and a measurement object on the samefrequency, which is currently under discussion of 3GPP.

FIG. 32 is a conceptual diagram in a case where comparison is madebetween a set component carrier and a component carrier on differentfrequency, which is currently under discussion of 3GPP.

FIG. 33 is a conceptual diagram illustrating a problem to be solved by afifth embodiment.

FIG. 34 is a sequence diagram showing the operation of a mobilecommunication system in a solution according to the fifth embodiment.

FIG. 35 is a conceptual diagram showing the state of a serving basestation and a neighbor base station in the solution according to thefifth embodiment.

FIG. 36 is a sequence diagram showing the operation of a mobilecommunication system in a solution according to a second modification ofthe fifth embodiment.

FIG. 37 is a sequence diagram showing the operation of a mobilecommunication system in a solution according to a third modification ofthe fifth embodiment.

FIG. 38 is a block diagram showing the configuration of a base station3308 in the solution according to the fifth embodiment.

EMBODIMENTS FOR CARRYING OUT THE INVENTION First Embodiment

FIG. 7 is a block diagram showing an overall configuration of an LTEmobile communication system, which is currently under discussion of3GPP. Currently, 3GPP is studying an overall system configurationincluding closed subscriber group (CSG) cells (Home-eNodeBs (Home-eNBand HeNB) of e-UTRAN, Home-NB (HNB) of UTRAN) and non-CSG cells (eNodeB(eNB) of e-UTRAN, NodeB (NB) of UTRAN, and BSS of GERAN) and, as toe-UTRAN, is proposing the configurations of (a) and (b) of FIG. 7(Non-Patent Document 1 and Non-Patent Document 3). FIG. 7A is nowdescribed. A user equipment (UE) 71 performs transmission/receptionto/from a base station 72. The base stations 72 are classified into aneNB (non-CSG cell) 72-1 and Home-eNBs (CSG cells) 72-2. The eNB 72-1 isconnected to MMEs 73 through interfaces S1, and control information iscommunicated between the eNB and the MMEs. A plurality of MMEs areconnected to one eNB. The Home-eNB 72-2 is connected to the MME 73through the interface S1, and control information is communicatedbetween the Home-eNB and the MME. A plurality of Home-eNBs are connectedto one MME.

Next, FIG. 7B is described. The UE 71 performs transmission/receptionto/from the base station 72. The base stations 72 are classified intothe eNB (non-CSG cell) 72-1 and the Home-eNBs (CSG cells) 72-2. As inFIG. 7A, the eNB 72-1 is connected to the MMEs 73 through the interfaceS1, and control information is communicated between the eNB and theMMEs. A plurality of MMEs are connected to one eNB. While, the Home-eNBs72-2 are connected to the MMEs 73 through a Home-eNB Gateway (HeNBGW)74. The Home-eNBs are connected to the HeGW by means of the interfacesS1, and the HeNBGW 74 is connected to the MMEs 73 through an interfaceS1_flex. One or a plurality of Home-eNBs 72-2 are connected to oneHeNBGW 74, and information is communicated therebetween through S1. TheHeNBGW 74 is connected to one or a plurality of MMEs 73, and informationis communicated therebetween through S1_flex.

With the configuration of FIG. 7B, one HeNBGW 74 is connected to theHome-eNBs belonging to the same CSG-ID. As a result, in the case wherethe same information such as registration information is transmittedfrom the MME 73 to a plurality of Home-eNBs 72-2 belonging to the sameCSG-ID, the information is transmitted to the HeNBGW 74 and thentransmitted to the plurality of Home-eNBs 72-2, with the result thatsignaling efficiency is enhanced more compared with the case where theinformation is directly transmitted to each of the plurality ofHome-eNBs 72-2. While, in the case where each Home-eNB 72-2 communicatesdedicated information with the MME 73, the information is merely causedto pass through the HeNBGW 74 (to be transparent) without beingprocessed, which allows communication in such a manner that the Home-eNB72-2 is directly connected to the MME 73.

FIG. 8 is a block diagram showing the configuration of the UE (equipment71 of FIG. 7 ) according to the present invention. The transmissionprocess of the UE shown in FIG. 8 is described. First, a transmissiondata buffer unit 803 stores the control data from a protocol processingunit 801 and the user data from an application unit 802. The data storedin the transmission data buffer unit 803 is transmitted to an encodingunit 804 and is subjected to encoding process such as error correction.There may exist the data output from the transmission data buffer unit803 directly to a modulating unit 805 without encoding process. The dataencoded by the encoding unit 804 is modulated by the modulating unit805. The modulated data is output to a frequency converting unit 806after being converted into a baseband signal, and then is converted intoa radio transmission frequency. After that, a transmission signal istransmitted from an antenna 807 to a base station 312. A UE 311 executesthe reception process as follows. The antenna 807 receives the radiosignal from the base station 312. The received signal is converted froma radio reception frequency to a baseband signal by the frequencyconverting unit 806 and is then demodulated by a demodulating unit 808.The demodulated data is transmitted to a decoding unit 809 and issubjected to decoding process such as error correction. Among the piecesof decoded data, the control data is transmitted to the protocolprocessing unit 801, while the user data is transmitted to theapplication unit 802. A series of process of the UE is controlled by acontrol unit 810. This means that, though not shown, the control unit810 is connected to the respective units (801 to 809).

FIG. 9 is a block diagram showing the configuration of the base station(base station 72 of FIG. 7 ) according to the present invention. Thetransmission process of the base station shown in FIG. 9 is described.An EPC communication unit 901 performs data transmission/receptionbetween the base station 72 and the EPCs (such as MME 73 and HeNBGW 74).A communication with another base station unit 902 performs datatransmission/reception to/from another base station. The EPCcommunication unit 901 and the communication with another base stationunit 902 respectively transmit/receive information to/from the protocolprocessing unit 903. The control data from the protocol processing unit903, and the user data and control data from the EPC communication unit901 and the communication with another base station unit 902 are storedin the transmission data buffer unit 904. The data stored in thetransmission data buffer unit 904 is transmitted to an encoding unit 905and is then subjected to encoding process such as error correction.There may exist the data output from the transmission data buffer unit904 directly to a modulating unit 906 without encoding process. Theencoded data is modulated by the modulating unit 906. The modulated datais output to a frequency converting unit 907 after being converted intoa baseband signal, and is then converted into a radio transmissionfrequency. After that, a transmission signal is transmitted from anantenna 908 to one or a plurality of UEs 71. While, the receptionprocess of the base station 72 is executed as follows. A radio signalfrom one or a plurality of UEs 311 is received by the antenna 908. Thereceived signal is converted from a radio reception frequency into abaseband signal by the frequency converting unit 907, and is thendemodulated by a demodulating unit 909. The demodulated data istransmitted to a decoding unit 910 and is then subjected to decodingprocess such as error correction. Among the pieces of decoded data, thecontrol data is transmitted to the protocol processing unit 903, EPCcommunication unit 901, or communication with another base station unit902, while the user data is transmitted to the EPC communication unit901 and communication with another base station unit 902. A series ofprocess by the base station 72 is controlled by a control unit 911. Thismeans that, though not shown, the control unit 911 is connected to therespective units (901 to 910).

FIG. 10 is a block diagram showing the configuration of a mobilitymanagement entity (MME) according to the present invention. A PDN GWcommunication unit 1001 performs data transmission/reception between anMME 73 and a PDN GW. A base station communication unit 1002 performsdata transmission/reception between the MME 73 and the base station 72through the S1 interface. In the case where the data received from thePDN GW is user data, the user data is transmitted from the PDN GWcommunication unit 1001 to the base station communication unit 1002through a user plane processing unit 1003 and is then transmitted to oneor a plurality of base stations 72. In the case where the data receivedfrom the base station 72 is user data, the user data is transmitted fromthe base station communication unit 1002 to the PDN GW communicationunit 1001 through the user plane processing unit 1003 and is thentransmitted to the PDN GW.

In the case where the data received from the PDN GW is control data, thecontrol data is transmitted from the PDN GW communication unit 1001 to acontrol plane control unit 1005. In the case where the data receivedfrom the base station 72 is control data, the control data istransmitted from the base station communication unit 1002 to the controlplane control unit 1005. A HeNBGW communication unit 1004 is provided inthe case where the HeNBGW 74 is provided, which performs datatransmission/reception by the interface (IF) between the MME 73 and theHeNBGW 74 according to an information type. The control data receivedfrom the HeNBGW communication unit 1004 is transmitted from the HeNBGWcommunication unit 1004 to the control plane control unit 1005. Theprocessing results of the control plane control unit 1005 aretransmitted to the PDN GW through the PDN GW communication unit 1001.The processing results of the control plane control unit 1005 aretransmitted to one or a plurality of base stations 72 by the S1interface through the base station communication unit 1002, and aretransmitted to one or a plurality of HeNBGWs 74 through the HeNBGWcommunication unit 1004.

The control plane control unit 1005 includes a NAS security unit 1005-1,an SAE bearer control unit 1005-2 and an idle state mobility managingunit 1005-3, and performs overall process for the control plane. The NASsecurity unit 1005-1 provides, for example, security of a non-accessstratum (NAS) message. For example, the SAE bearer control unit 1005-2manages a system architecture evolution (SAE) bearer. For example, theidle state mobility managing unit 1005-3 performs mobility management ofan idle state (LTE-IDLE state, which is merely referred to as idle aswell), generation and control of paging signaling in an idle state,addition, deletion, update and search of a tracking area (TA) of one ora plurality of UEs 71 being served thereby, and TA list management. TheMME begins a paging protocol by transmitting a paging message to thecell belonging to a TA) in which the UE is registered. The idle statemobility managing unit 1005-3 may manage the CSG of the Home-eNBs 72-2to be connected to the MME, CSG-IDs and a whitelist. In the CSG-IDmanagement, the relationship between a UE corresponding to the CSG-IDand the CSG cell is managed (added, deleted, updated or searched). Forexample, it may be the relationship between one or a plurality of UEswhose user access registration has been performed with a CSG-ID and theCSG cells belonging to this CSG-ID. In the whitelist management, therelationship between the UE and the CSG-ID is managed (added, deleted,updated or searched). For example, one or a plurality of CSG-IDs withwhich user registration has been performed by a UE may be stored in thewhitelist. Although other part of the MME 73 may perform those types ofCSG-related management, through execution by the idle state mobilitymanaging unit 1005-3, the method of using a tracking area code in placeof a CSG-ID, which is currently under discussion of 3GPP meeting, can beefficiently performed. A series of process by an MME 313 is controlledby a control unit 1006. This means that, though not shown, the controlunit 1006 is connected to the respective units (1001 to 1005).

FIG. 11 is a block diagram showing the configuration of the HeNBGWaccording to the present invention. An EPC communication unit 1101performs data transmission/reception between the HeNBGW 74 and the MME73 by the S1_flex interface. A base station communication unit 1102performs data transmission/reception between the HeNBGW 74 and theHome-eNB 72-2 by the S1 interface. A location processing unit 1103performs the process of transmitting, to a plurality of Home-eNBs, theregistration information or the like among the data transmitted from theMME 73 through the EPC communication unit 1101. The data processed bythe location processing unit 1103 is transmitted to the base stationcommunication unit 1102 and is transmitted to one or a plurality ofHome-eNBs 72-2 through the S1 interface. The data only caused to passthrough (to be transparent) without requiring the process by thelocation processing unit 1103 is passed from the EPC communication unit1101 to the base station communication unit 1102, and is transmitted toone or a plurality of Home-eNBs 72-2 through the S1 interface. A seriesof process by the HeNBGW 74 is controlled by a control unit 1104. Thismeans that, though not shown, the control unit 1104 is connected to therespective units (1101 to 1103).

Next, an example of a typical cell search method in a mobilecommunication system is described. FIG. 12 is a flowchart showing anoutline from cell search to idle state operation performed by a userequipment (UE) in the LTE communication system. When the cell search isstarted by the UE, in Step ST1201, the slot timing and frame timing aresynchronized by a primary synchronization signal (P-SS) and a secondarysynchronization signal (S-SS) transmitted from a nearby base station.Synchronization codes, which correspond to physical cell identities(PCIs) assigned per cell one by one, are assigned to the synchronizationsignals (SS) including the P-SS and S-SS. The number of PCIs iscurrently studied in 504 ways, and these 504 ways are used forsynchronization, and the PCIs of the synchronized cells are detected(identified). Next, in Step ST1202, a reference signal RS of thesynchronized cells, which is transmitted from the base station per cell,is detected and the received power is measured. The code correspondingto the PCI one by one is used for the reference signal RS, andseparation from other cell is enabled by correlation using the code. Thecode for RS of the cell is derived from the PCI identified in ST1201,which makes it possible to detect the RS and measure the RS receivedpower. Next, in ST1203, the cell having the best RS reception quality(for example, cell having the highest RS received power; best cell) isselected from one or more cells that have been detected up to ST1202. InST1204, next, the PBCH of the best cell is received, and the BCCH thatis the broadcast information is obtained. A master information block(MIB) containing the cell configuration information is mapped on theBCCH over the PBCH. Examples of MIB information include the down link(DL) system bandwidth (also referred to as transmission bandwidthconfiguration (dl-bandwidth)), transmission antenna number and systemframe number (SFN).

In 1205, next, the DL-SCH of the cell is received based on the cellconfiguration information of the MIB, to thereby obtain a systeminformation block (SIB) 1 of the broadcast information BCCH. The SIB1contains the information related to access to the cell, informationrelated to cell selection and scheduling information of other SIB (SIBk;k is an integer equal to or larger than 2). In addition, the SIB1contains a tracking area code (TAC). In ST1206, next, the UE comparesthe TAC received in ST1205 with the TAC that has been already possessedby the UE. In a case where they are identical to each other as a resultof comparison, the UE enters an idle state operation in the cell. In acase where they are different from each other as a result of comparison,the UE requires a core network (EPC) (including MME and the like) tochange a TA through the cell for performing tracking area update (TAU).The core network updates the TA based on an identification number (suchas a UE-ID) of the UE transmitted from the UE together with a TAUrequest signal. The core network updates the TA, and then transmits theTAU received signal to the UE. The UE rewrites (updates) the TAC (or TAClist) of the UE. After that, the UE enters the idle state operation inthe cell.

In the LTE and universal mobile telecommunication system (UMTS), theintroduction of a closed subscriber group (CSG) cell is studied. Asdescribed above, access is permitted for only one or a plurality of UEsregistered with the CSG cell. One or a plurality of UEs registered withthe CSG cell constitute one CSG. A specific identification numberreferred to as CSG-ID is added to the thus constituted CSG. Note thatone CSG may contain a plurality of CSG cells. After being registeredwith any one of the CSG cells, the UE can access the other CSG cells ofthe CSG to which the registered CSG cell belongs. Alternatively, theHome-eNB in the LTE or the Home-NB in the UMTS is used as the CSG cellin some cases. The UE registered with the CSG cell has a whitelist.Specifically, the whiltelist is stored in the SIM/USIM. The CSGinformation of the CSG cell with which the UE has been registered islisted in the whitelist. Specific examples of CSG information includeCSG-ID, tracking area identity (TAI) and TAC. Any one of the CSG-ID andTAC is adequate as long as they are associated with each other.Alternatively, GCI is adequate as long as the CSG-ID, TAC and globalcell identity (GCI) are associated with each other. As can be seen fromthe above, the UE which does not have a whitelist (including a casewhere the whitelist is empty in the present invention) is not allowed toaccess the CSG cell but is allowed to access only the non-CSG cell. Onthe other hand, the UE which has a whitelist is allowed to access theCSG cell of the CSG-ID with which registration has been performed aswell as the non-CSG cell.

3GPP discusses that all physical cell identities (PCIs) are split(referred to as PCI-split) into ones reserved for CSG cells and theothers reserved for non-CSG cells (Non-Patent Document 5). Further, 3GPPdiscusses that the PCI split information is broadcast in the systeminformation from the base station to the UEs being served thereby.Disclosed here is the basic operation of a UE by PCI split. The UE thatdoes not have the PCI split information needs to perform cell searchusing all PCIs (for example, using all 504 codes). On the other hand,the UE that has the PCI split information is capable of performing cellsearch using the PCI split information.

As disclosed in Non-Patent Document 7 and Non-Patent Document 8, 3GPP ispursuing specifications standard of “long term evolution advanced(LTE-A)” as Release 10.

It is considered in the LTE-A system that frequency bandwidths widerthan the frequency bandwidths (transmission bandwidths) of the LTEsystem are supported.

Therefore, an LTE-A-compliant UE is considered to simultaneously receiveone or a plurality of component carriers (CCs).

The LTE-A-support UE is considered to have the capability of carrieraggregation for simultaneous reception and transmission, only receptionor only transmission on a plurality of component carriers.

When the structure of the component carrier complies with the current3GPP (Release 8) specifications, an LTE-compliant UE is capable ofreception and transmission only on a single component carrier. TheLTE-compliant UE is also referred to as a 3GPP-Release-8-compliant UE.That is, it is considered that an LTE-compliant UE is operable orcompatible in the LTE-A system.

Non-Patent Document 8 describes the method of broadcasting the systeminformation in the LTE-A system. In addition, Non-Patent Document 8discloses a single carrier anchor and a multi carrier anchor in a basestation supports to carrier aggregation.

The single carrier anchor is capable of reception and transmission withan LTE-compliant UE. The single carrier anchor notifies the informationthat points to the carrier of a multicarrier anchor. The single carrieranchor broadcasts the current system information (SI) of 3GPP (Release8).

On the other hand, the multicarrier anchor is capable of reception andtransmission with an LTE-compliant UE. The multicarrier anchorbroadcasts the current system information (SI) of 3GPP (Release 8). Themulticarrier anchor broadcasts the multicarrier system information.

Non-Patent Document 10 proposes that in a base station (which may be acell) supports to carrier aggregation, a set of one or a plurality ofcomponent carriers, which are capable of data transmission/receptionwith a UE in RRC_CONNECTED state (merely referred to as RRC_CONNECTED aswell), is defined as a candidate component carrier set.

Further, Non-Patent Document 10 proposes that one or a plurality ofcomponent carriers on which data transmission/reception is performedpractically are defined as scheduling component carriers.

Non-Patent Document 11 discloses that, in supporting carrieraggregation, there is one transport block and one HARQ entity percomponent that performs data transmission/reception practically, thatis, per scheduling component. It is also disclosed that a transportblock is mapped to a single component only.

Note that the component is denoted by component carrier or CC in thefollowing.

Non-Patent Document 12 discloses the layer 2 structure for carrieraggregation. FIG. 13 shows the downlink layer 2 structure disclosed inNon-Patent Document 12, and FIG. 14 shows the uplink layer 2 structuredisclosed in Non-Patent Document 12.

In FIG. 13, 1301, 1302, 1303 and 1304 denote radio bearers. 1305, 1306,1307 and 1308 denote robust header compression (ROCH) entities. ROHC isan algorithm for performing header compression. 1309, 1310, 1311 and1312 denote security entities. 1313 is referred to as a packet dataconvergence protocol (PDCP) layer.

1314, 1315, 1316 and 1317 denote entities that perform segment, ARQ andthe like. 1318 denotes the entity of the logical channel BCCH. 1319denotes the entity of the logical channel PCCH. 1320 is referred to asan RLC layer.

1321, 1322, 1323 and 1324 denote logical channels.

1325 denotes the entity that performs scheduling and priority handling.1326 and 1327 denote the entities that perform segment on a componentbasis per UE. 1328, 1329, 1330, 1331, 1332 and 1333 denote HARQentities. 1334, 1335, 1336, 1337, 1338, 1339, 1340 and 1341 denotetransport channels. 1342 is referred to as a MAC layer.

In FIG. 14, 1401 and 1402 denote radio bearers. 1403 and 1404 denoteROHC entities. 1405 and 1406 denote security entities. 1407 is referredto as a PDCP layer.

1408 and 1409 denote entities that perform segment, ARQ and the like.1410 is referred to as an RLC layer.

1411 and 1412 denote logical channels.

1413 denotes the entity that performs scheduling and priority handling.1414 denotes the entity that performs segment on a component basis.1415, 1416 and 1417 denote HARQ entities. 1418, 1419 and 1420 denotetransport channels. 1421 is referred to as a MAC layer.

A problem to be solved by the first embodiment is described.

In a case where each transport block is mapped to a single componentonly, the following problem occurs.

The control information, as a specific example, RRC message is segmentedin the RLC layer, and then is mapped to the logical channel, forexample, DCCH or CCCH. In the MAC layer, a plurality of logical channelsDCCH or CCCH are multiplexed and are mapped to the transport channelDL-SCH. When being mapped to the transport channel DL-SCH, the pluralityof logical channels DCCH or CCCH are segmented into one or a pluralityof transport blocks (corresponding to MAC protocol data units (PDU)).Mapping of each transport block to one component results in that thecontrol information for a component, for example, RRC message is mappedto a plurality of components to be transmitted/received.

As an example, the process of a receiver is described with a downlinkRRC message.

A UE receives the physical channel PDSCH on one component, and obtainsone transport block on the transport channel DL-SCH as a result ofdemodulation and decoding. Suppose a case where segment into a pluralityof transport blocks in mapping to the transport channel by atransmitter, that is, base station. A UE processes the data segmentedinto transport blocks mapped on one or a plurality of components, tothereby obtain one transport channel. That is, there is no one-to-onecorrespondence between the RRC message and component used fortransmission/reception.

Therefore, it is unclear that the RRC message notified by means of theDCCH or CCCH mapped to the transport channel is the control informationcorresponding to what component, which causes a problem that the controlusing the RRC message cannot be performed in the base station supportsto carrier aggregation as a mobile communication system.

Further, the following problem occurs in a case where each transportchannel is mapped to a single component only.

The control information, as a specific example, RRC message is segmentedin the RLC layer, and then is mapped to the logical channel, forexample, DCCH or CCCH. In the MAC layer, a plurality of logical channelsDCCH or CCCH are multiplexed and are mapped to one or a plurality oftransport channels DL-SCH. In a case where each transport channel ismapped to one component, the RRC message being the control informationfor a component may be mapped to a plurality of components, or the RRCmessage being the control information for a component, for example,component A may be transmitted by a component other than this component,for example, component A.

As an example, the process of a receiver is described with a downlinkRRC message.

A UE receives the physical channel PDSCH on one component, and obtainsone transport channel DL-SCH as a result of demodulation and decoding,to thereby obtain the RRC message notified by means of the DCCH or CCCHmapped to this transport channel. However, there is no one-to-onecorrespondence between the RRC message and component used fortransmission/reception.

This causes a problem that the received RRC message is the controlinformation corresponding to what component is unclear.

The above-mentioned problem is specific to a mobile communication systemin which a frequency bandwidth is segmented in certain units, forexample, is segmented into so-called components in the case of LTE-Asystem, and those are aggregated to be used.

The solutions in the first embodiment are described below.

The first solution is described below.

In a base station supports to carrier aggregation, the controlinformation, as a specific example, the contents of the RRC message aremade common to all components. This enables judgment as to whether theRRC message received by a receiver is the control informationcorresponding to what component even if there is no one-to-onecorrespondence between the RRC message and the component used fortransmission/reception. Accordingly, there can be achieved an effectthat the control using the RRC message is enabled in a carrieraggregation mobile communication system.

The second solution is described below.

It is considered that the RRC message contains the control informationthat is efficient in component units without being common to allcomponents.

Description is given by taking the RRC message in the LTE system as aspecific example (Chapter 6.3.2 of Non-Patent Document 9).

The configuration information related to radio resources of the RRCmessage, as a specific example, “Radio resource Configuration” isconsidered to be efficient when being controlled per component. This isbecause the number of UEs performing transmission/reception inrespective components may vary, and accordingly the load status is notcommon to the respective components.

Further, as a specific example, it is considered to be efficient thatthe configuration information corresponding to a physical layer includedin “Radio resource Configuration”, as a specific example, “Physicalconfig Dedicated”, the configuration information related to the PDSCHincluded in “Physical config Dedicated” included in “Radio resourceConfiguration”, as a specific example, “pdsch-configdedicated”, or thetransmission power information of a reference signal included in“pdsch-configdedicated” included in “Physical config Dedicated” includedin “Radio resource Configuration”, as a specific example, “referenceSignalPower” is controlled per component. This is because the carrierfrequency varies among the respective components, and thus the radiopropagation characteristics are considered to vary. Accordingly, inorder to, for example, control the coverage areas within a substantiallyidentical range in the respective components, it is considered that thetransmission power of a reference signal in the respective componentsneeds to be dedicatedly controlled.

Further, it is considered to be efficient that the configurationinformation related to radio link failure of an RRC message, as aspecific example, “Radio link failure related action” or theconfiguration information related to measurement, as a specific example,“Measurement” is controlled per component. This is because the radiopropagation characteristics vary due to a difference of the carrierfrequency among the respective components, and thus dedicated control isconsidered to be efficient.

Accordingly, in a case of using the first solution, the control by anRRC message cannot be performed in component units. This causes aproblem that control cannot be performed in accordance with a componentload or control cannot be performed in accordance with the radiocharacteristics of carrier frequency of a component.

In the second solution for solving the above-mentioned problem, in abase station supports to carrier aggregation, one componenttransmits/receives the control information, as a specific example, oneRRC message, or one component transmits/receives a plurality of RRCmessages. That is, an RRC message is prevented from being segmented by aplurality of components to be transmitted/received.

Further, the logical channels to which an RRC message is mapped, forexample, the DCCH or CCCH is mapped to one transport channel, forexample, DL-SCH. That is, the logical channel to which an RRC message ismapped, for example, the DCCH or CCCH is not segmented into a pluralityof transport channels, for example, DL-SCHs.

Further, the logical channel to which an RRC message is mapped, forexample, the DCCH or CCCH is mapped on one transport block. That is, theRRC message is not segmented into a plurality of transport blocks but ismapped to one transport channel, for example, DL-SCH.

Further, an RRC message transmitted by a transmitter is mapped to thecomponent controlled by the RRC message.

Further, the RRC message received by a receiver is the controlinformation related to the component on which the RRC message has beenreceived.

This enables a receiver to associate the component used fortransmission/reception with the RRC message, specifically, identify thephysical information (such as frequency) of the component associatedwith an RRC message. Therefore, it is possible to achieve an effect thatcommunication control using an RRC message can be achieved efficientlyin a carrier aggregation mobile communication system.

Moreover, the second solution allows the transmission/reception of thecomponent-unit RRC message. This achieves effects that control can beperformed in accordance with the component load and that control can beperformed in accordance with the radio characteristics of carrierfrequency of a component.

The third solution is described below.

An amount of information that can be transmitted/received by onetransport block varies depending on a radio environment. That is, anamount of information that can be transmitted/received by one transportblock is large in a case of a good radio environment between a basestation and a UE, whereas an amount of information that can betransmitted/received by one transport block is small in a case of a poorradio environment.

Therefore, a case where the RRC message is transmitted/received by onetransport block irrespective of a radio environment with the secondsolution causes a problem that the amount of information of an RRCmessage needs to be limited to the least amount of information that canbe transmitted/received by one transport block.

The use of the second solution causes a problem that a mobilecommunication system becomes more complicated, for example, the controlinformation transmitted/received with one RRC message in a currentmobile communication system needs to be transmitted/received by aplurality of RRC messages.

In the third solution for solving the above-mentioned problem, in a basestation supports to carrier aggregation, the information indicating thatthe RRC message is the control information corresponding to whatcomponent is added to the RRC message or as an element of the RRCmessage. In other words, the information for identifying the physicalinformation of a corresponding component carrier is added.

Alternatively, another field different from that for RRC message isprovided in a base station supports to carrier aggregation, and theinformation indicating that the RRC message is the control informationcorresponding to what component is added to the another area. Anotherarea may be added to or multiplexed in the RLC layer, or may be added toor multiplexed in the MAC layer. Specific examples of another areainclude a header and a footer. Specific examples of the header include aheader (RLC header) added to RLC SDU, a header (MAC header) added to MACSDU and a header (MAC header) added to the MAC control area (MAC controlelement). Specific examples of the footer include a MAC control area.

This enables the receiver to associate the component used fortransmission/reception with an RRC message, specifically, identify thephysical information of a component associated with the RRC message.Accordingly, it is possible to achieve an effect that communicationcontrol with an RRC message can be efficiently performed in a carrieraggregation mobile communication system.

Further, it is possible to transmit/receive a component-unit RRCmessage. This results in effects that control can be performed inaccordance with a component load and that control can be performed inaccordance with the radio characteristics of carrier frequency of acomponent.

Moreover, it is not required to limit the amount of information of anRRC message, and an effect that a mobile communication system isprevented from becoming complicated can be achieved.

Specific examples of the information indicating the control informationcorresponding to what component are described below.

The first specific example is carrier frequency of a component.Description is given with reference to FIG. 15 . 1501 to 1507 denotecomponents capable of carrier aggregation in the base station. f1 to f10denote carrier frequencies of components of the respective components.In the first specific example, the carrier frequency of a componentshown in FIG. 15 is used as the information indicating the controlinformation corresponding to what component. As a specific example, in acase of the control information corresponding to the component 1504 ofFIG. 15 , the information of the carrier frequency of a component f6 isadded as the element in the RRC message. This specific example isadvantageous in that a carrier frequency change of a mobilecommunication system can be responded in a flexible manner becausevalues which are absolute are mapped.

The horizontal axis represents frequency in FIG. 15 . The DL frequencyis different from the UL frequency in FDD but, for simplification, theDL frequency and the UL frequency are shown on the same axis. Similarly,for simplification, downlink components (downlink CCs, DL CCs) aretreated identically to uplink components (uplink CCs, UL CCs)respectively corresponding to (forming a pair of bands with) DL CCs,which are denoted by 1501 to 1507 in the diagram. Not only limitedthereto, the arrangement order on the frequency axis may vary betweenthe downlink CC and uplink CC corresponding thereto.

In this specification, downlink CC and uplink CC corresponding thereto(forming a pair of bands) together are referred to as CC unlessotherwise noted.

The second specific example is an identifier of a component. Descriptionis given with reference to FIG. 16 . The same reference symbols as thoseof FIG. 15 denote equivalent portions, and thus description thereof isomitted. 1501 to 1507 and 1601 to 1603 denote components used as amobile communication system. In the second specific example, identifiersof components shown in FIG. 16B are used as the information indicatingthe control information corresponding to what component. Carrierfrequencies being the physical information of the components (1501 to1507 and 1601 to 1603) used as a mobile communication system, forexample, LTE-A system are associated with identifiers of components(FIG. 16B). As a specific example, in the case of the controlinformation corresponding to the component 1504 of FIG. 16 , theinformation of an identifier of a component “CC #6” is added as theelement of an RRC message. The receiver that has received the identifierof a component “CC #6” as the element of an RRC message recognizes that“CC #6” represents the carrier frequency of a component f6 based on thecorrespondence list of carrier frequencies of components used as amobile communication system and identifiers of components, which isshown in FIG. 16B. The absolute value is mapped in the first specificexample, whereas an identifier is mapped in the second specific example.Therefore, a smaller amount of information added as the element of anRRC message, that is, a smaller information bit number is required inthe second specific example. This leads to an effect that radioresources are effectively used.

The correspondence list of carrier frequencies of components used as amobile communication system and identifiers of components, which isshown in FIG. 16B, is notified from a network to a UE. As a specificexample of the notification method, a base station may notify a UE bymeans of the broadcast information, as a specific example, BCCH (MIB orSIB). As a result of the network notifying the UE of the association, itis possible to achieve an effect that an amount of information added asthe element of an RRC message is reduced while maintaining an advantagethat a carrier frequency change of a mobile communication system can beresponded in a flexible manner.

Alternatively, the correspondence list of carrier frequencies ofcomponents used as a mobile communication system and identifiers ofcomponents, which is shown in FIG. 16B, may be determined in a staticmanner as a mobile communication system. This eliminates the need tonotify the correspondence list from a network to a UE, whereby it ispossible to achieve effects that radio resources are effectively usedand that a communication error accompanying radio communication does notoccur.

The third specific example is an identifier of a component. Descriptionis given with reference to FIG. 17 . The same reference symbols as thoseof FIG. 15 denote equivalent portions, and thus description thereof isomitted. In the third specific example, identifiers of components shownin FIG. 17B are used as the information indicating the controlinformation corresponding to what component. The carrier frequencies ofcomponents used in the base station are associated with the identifiersof components (FIG. 17B). As a specific example, in the case of thecontrol information corresponding to the component 1504 of FIG. 17 , theinformation of an identifier of a component “CC #4” is added as theelement of an RRC message. The receiver that has received the identifierof a component “CC #4” as the element of an RRC message recognizes that“CC #4” represents the carrier frequency of a component f6 based on thecorrespondence list of carrier frequencies of components and identifiersof components, which is shown in FIG. 17B. The absolute value is mappedin the first specific example, and the identifier corresponding to thecarrier frequency of a component that can be taken by a mobilecommunication system is mapped in the second specific example. On theother hand, in the third specific example, an identifier correspondingto carrier frequency of a component that can be taken by the basestation is mapped. Therefore, a smaller amount of information added asthe element of an RRC message, that is, a smaller information bit numberis required in the third specific example. This achieves an effect thatradio resources are effectively used.

The correspondence list of carrier frequencies of components andidentifiers of components, which is shown in FIG. 17B, is notified froma network to a UE. As a specific example of the notification method, abase station notifies a UE by means of the broadcast information, as aspecific example, BCCH (MIB or SIB). As a result of the networknotifying the UE of the association information (correspondence list),it is possible to achieve an effect that an amount of information addedas the element of an RRC message is reduced while maintaining theadvantage that a carrier frequency change of a mobile communicationsystem can be responded in a flexible manner.

Specific examples of numbering of identifiers of components aredescribed below.

As the first specific example, components are numbered consecutively asa mobile communication system, as an LTE-A system or as the basestation. As a specific example of consecutive numbering, numbering isperformed in an ascending order from a low frequency as shown in FIG.18A or in a descending order from a high frequency.

As the second specific example, components included in a frequency bandare numbered consecutively per frequency band as a mobile communicationsystem, as an LTE-A system or as the base station. The frequency bandrepresents a partial set including one or more components with respectto all components, which represents a set of components having commonphysical characteristics or radio characteristics. In systems such asUTRA, LTE and LTE-A, uplink and downlink are designed so as to enable anoperation at frequency bands composed of several consecutivefrequencies. Each of those consecutive frequency bands is referred to asa frequency band. As a specific example of consecutive numbering,numbering is performed in an ascending order from a low frequency asshown in FIG. 18B or in a descending order from a high frequency perfrequency band. In this case, when the identifiers of componentsdescribed in the second specific example or third specific example areused as the information indicating the control information correspondingto what component, the frequency band and identifier of a componentindicate the control information corresponding to what component.

FIG. 19 shows an example of the operation. Description is given usingthe third specific example as the information indicating the controlinformation corresponding to what component.

In Step ST1901, a base station broadcasts the correspondence list ofcarrier frequencies of components used in the base station andidentifiers of components, for example, FIG. 17B to UEs being servedthereby.

In Step ST1902, the UE receives, from the base station, thecorrespondence list of carrier frequencies of components used in thebase station and identifiers of components.

In Step ST1903, the base station adds the information indicating thatthe RRC message is the control information corresponding to whatcomponent, as the element of an RRC message being the component-unitcontrol information. For example, in a case of the control informationcorresponding to the component 1504 of FIG. 17A, the base station addsthe information of the identifier of a component “CC #4” as the elementof an RRC message.

In Step ST1904, the base station segments the RRC message (RLC PDU) andmaps those to the logical channel, for example, DCCH.

In Step ST1905, the base station multiplexes one or a plurality oflogical channels and segments those into one or a plurality of transportblocks (MAC PDUs).

In Step ST1906, the base station maps the segmented transport blocks(MAC PDUs) to one transport channel DL-SCH or one of a plurality oftransport channels DL-SCHs.

In Step ST1907, the base station maps the respective transport blocks toa physical channel PDSCH on one component (also referred to as CC).

In Step ST1908, the base station transmits the PDSCH to the UE.

In Step ST1909, the UE receives the PDSCH on each component.

In Step ST1910, the UE performs demodulation and decoding, to therebyobtain one transport block on the transport channel DL-SCH.

In Step ST1911, the UE processes the data segmented into the transportblocks mapped to the transport channel DL-SCH, and accordingly in StepST1912, the UE obtains the DCCH.

In Step ST1913, the UE obtains the RRC message mapped on the DCCH.

In Step ST1914, the UE obtains an identifier of a component in the RRCmessage. For example, the UE obtains the identifier of a component “CC#4” of FIG. 17 .

In Step ST1915, the UE obtains the carrier frequency of a component ofthe component controlled by the RRC message, based on the correspondencelist of carrier frequencies of components used by the base station andidentifiers of components, which has been received in Step ST1902. Forexample, the UE obtains the corresponding carrier frequency of acomponent “f6” based on the identifier of a component “CC #4” obtainedin Step ST1914 from FIG. 17B.

In Step ST1916, the UE executes, on the carrier frequency of a componentobtained in Step ST1915, the control instructed by the RRC messagereceived in Step ST1913.

Further, in a case where the RRC message contains the component-unitcontrol information and the control information for all components ofthe UE in a base station supports to carrier aggregation, the followingproblem occurs.

In a case where the solutions in the first embodiment are applied to thecontrol information for all components, for example, the informationindicating all carrier frequencies of components needs to be added as anelement of an RRC message. This results in a large-volume informationindicating that the RRC message is the control information correspondingto what component, leading to a problem that radio resources cannot beeffectively used.

Solutions to this are described below.

In the first solution, in a base station supports to carrieraggregation, the information indicating that the RRC message is thecontrol information for all components is added to the RRC message or asan element of the RRC message, separately from the informationindicating that the RRC message is the control information correspondingto what component.

Alternatively, in a base station supports to carrier aggregation,another area is provided separately from that for RRC message, and theinformation indicating that the RRC message is the control informationfor all components is added separately from the information indicatingthat the RRC message is the control information corresponding to whatcomponent. A specific example of another area is similar to the above,and thus description thereof is omitted.

This enables to judge whether the RRC message received by the receiveris the control information corresponding to what component, and besides,enables to judge whether the received RRC message is the informationcorresponding to all components while preventing an increase in amountof information to be added as an element of the RRC message.

In the second solution, in a base station supports to carrieraggregation, only the information indicating that the RRC message is thecontrol information corresponding to what component is added to an RRCmessage or as an element of the RRC message. In a case where the RRCmessage is the control information corresponding to all components, theinformation indicating that the RRC message is the control informationcorresponding to what component is not added to the RRC message or as anelement of the RRC message.

As a result, if the information indicating the control informationcorresponding to what component is not added to the RRC message receivedby the receiver, it is possible to judge whether the RRC message is thecontrol information corresponding to all components.

Differently from the first solution, the second solution eliminates theneed to newly provide the information indicating that an RRC message isthe control information corresponding to all components, whereby aneffect that a mobile communication system is prevented from becomingcomplicated can be achieved. In addition, an effect that radio resourcesare effectively used can be achieved.

While the first embodiment has mainly described a downlink RRC message,the first embodiment is also applicable to an uplink RRC message.

In addition to the logical channels DCCH and CCCH, the logical channelMCCH and the logical channel BCCH are also mapped to the transportchannel DL-SCH by the control information. The first embodiment issimilarly applicable to the MCCH and BCCH.

The first embodiment can achieve the following effects.

The information indicating that the RRC message is the controlinformation corresponding to what component is added to the RRC messageor as an element of the RRC message. In other words, the physicalinformation of the component corresponding to the RRC message is madeidentifiable, which allows the receiver to judge whether the RRC messagenotified by means of the DCCH or CCCH mapped to the transport channel isthe control information corresponding to what component.

Therefore, it is possible to efficiently perform communication controlwith the use of an RRC message as a mobile communication system, whichdoes not require the control by another message, leading to an effectthat a mobile communication system is prevented from becomingcomplicated.

Second Embodiment

A problem to be solved by a second embodiment is described.

The following problem arises in a case where each transport block ismapped to a single component only.

The control information, as a specific example, MAC message is mapped tothe transport channel, for example, DL-SCH. The MAC message is segmentedinto one or a plurality of transport blocks when being mapped to thetransport channel DL-SCH. If each transport block is mapped to acomponent, the control information corresponding to this component, forexample, MAC message is resultantly mapped to a plurality of componentsto be transmitted/received.

Description is given with the use of, for example, a downlink MACmessage. A UE receives the physical channel PDSCH on one component andperforms demodulation and decoding, to thereby obtain one transportblock on the transport channel DL-SCH. Suppose the case where data hasbeen segmented into a plurality of transport blocks when a transmitter,that is, a base station maps the data to a transport channel. The UEprocesses the data segmented into the transport blocks mapped to one ora plurality of components, to thereby obtain one transport channel. Thatis, the MAC message and the component used for transmission/receptionhave no one-to-one correspondence.

Accordingly, whether the MAC message mapped to the transport channel isthe control information corresponding to what component is unclear,which causes a problem that control with the use of a MAC message cannotbe performed as a mobile communication system.

Further, in a case where each transport channel is mapped to a singlecomponent only, the following problem arises.

The control information, as a specific example, a MAC message is mappedto a transport channel, for example, DL-SCH. If each transport channelis mapped to one component, the MAC message being the controlinformation for a component may be resultantly mapped to a plurality ofcomponents, or the MAC message being the control information for acomponent, for example, component A may be resultantly transmitted by acomponent other than this component, for example, component A.

Description is given with the use of, for example, downlink. A UEreceives the physical channel PDSCH on one component and obtains onetransport channel DL-SCH as a result of demodulation and decoding, tothereby obtain a MAC message mapped to the transport channel. However,the MAC message and the component used for transmission/reception haveno one-to-one correspondence.

Accordingly, there arises a problem as to whether the received MACmessage is the control information corresponding to what component isunclear.

The above-mentioned problem is specific to a mobile communication systemin which a frequency band is divided in certain units, which arereferred to as components in the LTE-A system, and those are used byaggregation.

Solutions in the second embodiment are described below.

The first solution is described below.

In a base station which supports to carrier aggregation, the controlinformation, as a specific example, the contents of a MAC message aremade common to all components. As a result, even if the MAC message andthe component used for transmission/reception have no one-to-onecorrespondence, it is possible to judge whether the MAC message receivedby a receiver is the control information corresponding to whatcomponent. There can be achieved an effect that control with the use ofa MAC message is allowed in a carrier aggregation mobile communicationsystem.

The second solution is described below.

Suppose the MAC message contains the control information that isefficient if it is not common to all components but is in componentunits.

Description is given by taking the MAC message of the LTE system as aspecific example (Non-Patent Document 13).

It is considered efficient to control the information indicating channelcoding and decoding, interleaving, rate matching and the like of the MACmessage, as a specific example, “Transport format” and “Transport formatset” per component. This is because the carrier frequency varies amongcomponents, and thus the radio propagation characteristics areconsidered to vary. Therefore, it is considered that “Transport format”needs to be dedicatedly selected by the respective components for theselection of optimum “Transport format” by the respective components.

Further, it is considered that the information used for reporting to abase station, by a UE, a difference between the UE maximum transmissionpower and the estimated transmission power used for UL-SCH transmission,as a specific example, “Power Headroom reporting” varies amongcomponents. This is because the carrier frequency varies amongcomponents, and thus radio propagation characteristics are considered tovary. Therefore, it may be considered that the transmission power usedfor UL-SCH transmission of a UE also varies from component to component,and thus it is necessary to allow “Power Headroom Reporting” to bereported dedicatedly on the respective components.

Accordingly, in a case of using the first solution, control by a MACmessage cannot be performed in component units, causing a problem thatcontrol cannot be performed in accordance with radio characteristics ofthe carrier frequency of a component.

In the second solution for solving the above-mentioned problem, in abase station supports to carrier aggregation, the control information,as a specific example, one MAC message is transmitted/received by onecomponent, or a plurality of MAC messages are transmitted/received byone component. That is, the MAC message is prevented from beingtransmitted/received by being segmented into a plurality of components.

Further, a transport channel to which a MAC message is mapped, forexample, DL-SCH is mapped to one transport block. That is, a transportchannel to which a MAC message is mapped, for example, DL-SCH is notdivided into transport blocks.

Further, a MAC message transmitted by a transmitter is mapped to thecomponent controlled by the MAC message.

Further, the MAC message received by a receiver is the controlinformation related to the received component.

This enables association of the component used fortransmission/reception and MAC message by a receiver. In other words, itis possible to identify the physical information of the componentcorresponding to a MAC message. This achieves an effect that thecommunication control using a MAC message can be performed efficientlyin a mobile communication system supports to carrier aggregation.

Moreover, the second solution allows the transmission/reception of acomponent-unit MAC message. This achieves an effect that control can beperformed in accordance with radio characteristics of component charierfrequency.

The third solution is described below.

An amount of information that can be transmitted/received by onetransport block depends on a radio environment. That is, an amount ofinformation that can be transmitted/received by one transport block islarge in a case of a good radio environment between a base station and aUE, whereas an amount of information that can be transmitted/received byone transport block is small in a case of a poor radio environment.

Therefore, a case where the MAC message is transmitted/received by onetransport block irrespective of a radio environment with the secondsolution causes a problem that the amount of information of a MACmessage needs to be limited to the least amount of information that canbe transmitted/received by one transport block.

The use of the second solution causes a problem that a mobilecommunication system becomes more complicated, for example, the controlinformation transmitted/received by one MAC message in a current mobilecommunication system needs to be transmitted/received by a plurality ofMAC messages.

In the third solution for solving the above-mentioned problem, in a basestation supports to carrier aggregation, the information indicating thatthe MAC message is the control information corresponding to whatcomponent is added to the MAC message or as an element of the MACmessage. In other words, the information for identifying the physicalinformation of a component corresponding to the MAC message is added.

Alternatively, another area different from that for MAC message isprovided in a base station supports to carrier aggregation, and theinformation indicating that the MAC message is the control informationcorresponding to what component is added to the another area. Anotherarea may be added to or multiplexed in the MAC layer. Specific examplesof another area include a header and a footer. Specific examples of theheader include a header (MAC header) added to MAC SDU and a header (MACheader) added to the MAC control area (MAC control element). Specificexamples of the footer include a MAC control area.

This enables the receiver to associate the component used fortransmission/reception with the MAC message. In other words, thephysical information of a component corresponding to the MAC message isidentifiable. Accordingly, it is possible to achieve an effect thatcommunication control with a MAC message can be efficiently performed ina mobile communication system supports to carrier aggregation.

Further, it is possible to transmit/receive a component-unit MACmessage. This results in an effect that control can be performed inaccordance with the radio characteristics of carrier frequency of acomponent.

Moreover, it is not required to limit the amount of information of a MACmessage, and an effect that a mobile communication system is preventedfrom becoming complicated can be achieved.

A similar method to that of the first embodiment can be used as aspecific example of the information indicating the control informationcorresponding to what component. Therefore, description thereof isomitted.

A similar method to that of the first embodiment can be used as aspecific example of numbering of identifiers of components. Therefore,description thereof is omitted.

FIG. 20 shows an example of the operation. Description is given with theuse of the third specific example as the information indicating thecontrol information corresponding to what component. In FIG. 20 ,identical or equivalent process is performed in the steps of the samereference numerals as those of FIG. 19 , and thus description of thesteps of the same reference numerals is omitted.

In Step ST2001, a base station adds the information indicating that theMAC message is the control information corresponding to what componentas an element of the MAC message being the control component-unitinformation. For example, in the case of the control informationcorresponding to the component 1504 of FIG. 17 , the base station addsthe information of the identifier of a component “CC #4” as the elementof a MAC message.

In Step ST2002, the base station segments the MAC message into one or aplurality of transport blocks (MAC PDUs).

In Step ST2003, the UE obtains the MAC message mapped on the DL-SCH.

In Step ST2004, the UE obtains an identifier of a component in the MACmessage. For example, the UE obtains the identifier of a component “CC#4” of FIG. 17 .

In Step ST2005, the UE executes, for the carrier frequency of acomponent obtained in Step ST1915, the control instructed by the MACmessage received in Step ST2003.

Further, in a base station supports to carrier aggregation, it ispossible to use a method similar to that of the first embodiment as thesolution to a problem in a case where the MAC message contains thecomponent-unit control information and the control informationcorresponding to all components of the base station. Therefore,description thereof is omitted.

While the downlink MAC message has been mainly described in the secondembodiment, the second embodiment is similarly applicable to an uplinkMAC message.

In addition to the logical channels DCCH and CCCH, the logical channelMCCH and logical channel BCCH are mapped to the transport channel DL-SCHby the control information. The second embodiment is similarlyapplicable to the MCCH and BCCH.

The second embodiment can achieve the following effects.

The information indicating that the MAC message is the controlinformation corresponding to what component is added to the MAC messageor as an element of the MAC message, which allows the receiver to judgewhether the MAC message notified by means of the transport channel isthe control information corresponding to what component. In other words,the information for identifying the physical information of a componentcorresponding to the MAC message is added, whereby it is possible toidentify the physical information of a component corresponding to theMAC message by the receiver.

Therefore, it is possible to efficiently perform communication controlwith the use of a MAC message as a mobile communication system, and thusthe control by another message is not required. Accordingly, an effectthat a mobile communication system is prevented from becomingcomplicated can be achieved.

First Modification of Second Embodiment

A problem to be solved by a first modification of the second embodimentis similar to that of the second embodiment, and thus descriptionthereof is omitted.

A solution in the first modification of the second embodiment isdescribed below.

A base station supports to carrier aggregation has a MAC layer structureso as to separate the portion into which a MAC message being thecomponent-unit control information is inserted from the portion intowhich a MAC message being the control information for all components ofthe base station is inserted.

A specific example of the method of separating the MAC layer structureis described below.

FIG. 21 shows the downlink MAC layer structure, and FIG. 22 shows theuplink MAC layer structure. The same reference numerals as those of FIG.13 denote equivalent portions in FIG. 21 , and thus description thereofis omitted. The same reference numerals as those of FIG. 14 denoteequivalent portions in FIG. 22 , and thus description thereof isomitted.

The portion into which a MAC message being the component-unit controlinformation in the transmitter is positioned downstream of the positionfor the separation in component units per UE. 2101 of FIG. 21 and 2201of FIG. 22 denote the portions into which a MAC message being thecomponent-unit control information is inserted. The MAC message to betransmitted is inserted so as to be transmitted by the componentcontrolled by the MAC message.

The portion into which a MAC message being the control information forall components is inserted in the transmitter is positioned upstream ofthe separation in component units per UE. 2102 of FIG. 21 and 2202 ofFIG. 22 denote the portions into which a MAC message being the controlinformation for all components is inserted.

The MAC message that can be received by the physical channel PDSCH onone component in the receiver is judged as a component-unit message. Thecomponent-unit MAC message can be judged as the control information forthe component that has received the MAC message.

On the other hand, the MAC message that can be received by the physicalchannels PDSCH on a plurality of components in the receiver is judged asthe MAC message being the control information for all components.

The first modification of the second embodiment can achieve similareffects to those of the second embodiment.

The receiver can identify the physical information of the componentcorresponding to the MAC message.

Therefore, it is possible to efficiently perform communication controlwith the use of a MAC message as a mobile communication system, and thuscontrol by another message is not required. This achieves an effect thata mobile communication system is prevented from becoming complicated.

Differently from the second embodiment, it is not necessary to add theinformation for identifying the physical information of a componentcorresponding to a MAC message. This achieves effects that radioresources are effectively used and that a mobile communication system isprevented from becoming complicated.

Third Embodiment

A problem to be solved by the third embodiment is described.

In a case of using the solutions of the first embodiment, the problem asto whether the RRC message received by the receiver is the controlinformation corresponding to what component is unclear is solved.

In a base station supports to carrier aggregation, one or a plurality ofcomponents are scheduled for a UE in accordance with a change in radioenvironment, as a specific example, in accordance with the CQI measuredby a UE and measurement results. Therefore, the component to bescheduled varies in time for a UE.

In the solutions of the first embodiment, higher layers, as a specificexample thereof, higher layers that control an RRC message need torecognize the scheduling results of components for a UE. Therefore, acase where a component carrier scheduled for a UE varies leads to a casewhere, in the solutions of the first embodiment, the layer that controlsan RRC message does not follow scheduling of component carriers. As aresult, there occurs a case where the component, which has beenspecified by the information indicating that the RRC message is thecontrol information corresponding to what component in the RRC message,is not included in the component that has been practically allocated toa UE.

Accordingly, in a case where, for example, a component scheduled for aUE varies, a problem as to whether the received RRC message is thecontrol information corresponding to what component is unclear arisesagain.

Solutions in the third embodiment are described below.

The first solution is described below.

The layer that performs scheduling of components notifies a higherlayer, as a specific example, a layer into which an RRC message isinserted of the scheduling results of components for a UE. As a specificexample, a MAC layer being a layer that schedules components notifies anRRC layer being a layer into which an RRC message is inserted of thescheduling results of components for a UE.

An RRC message is used for notification of components scheduled for a UEfrom a base station. The RRC message is notified by the method disclosedin the first embodiment simultaneously with the notification of thecomponents to be scheduled. The notification of components to bescheduled and the notification of an RRC message disclosed in the firstembodiment may be performed simultaneously or not.

This allows the layer that controls an RRC message to always knowscheduling of component carriers. That is, the layer can followscheduling.

Accordingly, the above-mentioned problem in the third embodiment issolved.

The second solution is described below.

In a case of using the first solution, the layer that controls an RRCmessage cannot notify the components to be scheduled and cannot notifythe RRC message before recognizing the scheduling results of componentsfor a UE, causing a problem of an increase in control delay as a mobilecommunication system.

In the second solution for solving the above-mentioned problem, in abase station supports to carrier aggregation, not the informationindicating that the RRC message is the control information correspondingto what component, but a component index is added to another areadifferent from that for an RRC message, for example, a header or footer,to the RRC message or as an element of the RRC message.

A component index is an identifier that should satisfy the followingrequirements: (1) it should be an identifier mainly used by a higherlayer; (2) it should be irrelevant to the physical information (forexample, frequency) of a component carrier; and (3) it should be theinformation for identifying a component (information by which thephysical information of a component carrier cannot be identified).

As to the component index, a higher layer notifies a MAC layer of thecontrol information corresponding to the same component with the use ofthe same component index, and the control information corresponding to adifferent component with the use of a different component index.

A higher layer shows the control information corresponding to the samecomponent or the control information corresponding to a differentcomponent by a component index. A specific example of the MAC layer towhich a higher layer notifies a component index is described below.

(1) Scheduling of components is performed, which is referred to as acomponent scheduling block. Scheduling of components is performed by CQIand measurement report in which a UE measures a radio environment andreports to a base station.

(2) Component-unit segmentation is performed per UE, which are denotedby, for example, 1326 and 1327 of FIG. 13 .

Hereinafter, description is given with the use of a “componentscheduling block” as a specific example of the MAC layer.

The component scheduling block associates a component index with acomponent to be scheduled to a UE. The component scheduled to a UE and acomponent used for data transmission/reception between a UE and a basestation are referred to as scheduling components.

A specific example of association of a component index with a schedulingcomponent is described below. (1) One type of component index isassociated with one scheduling component. (2) One type of componentindex is associated with a plurality of types of scheduling components.

Specific examples of the information indicating a scheduling componentare described below.

The first specific example is carrier frequency of a component.Description is given with reference to FIG. 23A. 2301 to 2307 denotecomponents that perform carrier aggregation in the base station. f1 tof10 denote carrier frequencies of components of the respectivecomponents. In the first specific example, the carrier frequencies ofcomponents shown in FIG. 23 are used as the information indicating thescheduling components. As a specific example, in a case where thescheduling components allocated to a UE 2308 are the component 2302 andthe component 2304, the information indicating the scheduling componentis “f2” and “f6”. This specific example is advantageous that a carrierfrequency change of a mobile communication system can be responded in aflexible manner because values which are absolute are used.

As shown in FIG. 23B, the carrier frequencies of components are used asthe information indicating the scheduling component used for associationof a component index and a scheduling component.

The second specific example is an identifier of a component. Descriptionis given with reference to FIG. 24A. The same reference symbols as thoseof FIG. 23 denote the equivalent portions, and thus description thereofis omitted. 2301 to 2307 and 2401 to 2403 denote components used as amobile communication system. In the second specific example, theidentifiers of components shown in FIG. 24B are used as the informationindicating the scheduling components. The carrier frequencies ofcomponents (2301 to 2307 and 1401 to 2403) used as a mobilecommunication system, for example, an LTE-A system are associated withthe identifiers of components. As a specific example, an identifier of acomponent “CC #2” corresponds to the information indicating thescheduling component 2302 of FIG. 24A. An identifier of a component “CC#6” corresponds to the information indicating the scheduling component2304 of FIG. 24A.

Differently from the first specific example using values which areabsolute, identifiers are mapped in the second specific example.Therefore, an amount of information indicating scheduling components,that is, the information bit number is smaller in the second specificexample. This has an effect that radio resources are effectively used.

The correspondence list of carrier frequencies of components andidentifiers of components, which is shown in FIG. 24B, is notified froma network to a UE. As a specific example of the notification method,notification is made from the base station to the UE by means of the useof broadcast information, as a specific example, the BCCH (MIB or SIB).The association is notified from the network to the UE, which achievesan effect that an amount of information indicating scheduling componentscan be reduced while maintaining an advantage that a carrier frequencychange of a mobile communication system.

Alternatively, the correspondence list of carrier frequencies ofcomponents and identifiers of components, which is shown in FIG. 24B,may be determined in a static manner as a mobile communication system.This eliminates the need to notify the correspondence list from anetwork to a UE, leading to effects that radio resources are effectivelyused and that a communication error does not occur accompanying radiocommunication.

As shown in FIG. 24C, the above-mentioned identifiers of components areused as the information indicating the scheduling components used forassociation of component indices and scheduling components.

The third specific example is an identifier of a component. Descriptionis given with reference to FIG. 25 . The same reference symbols as thoseof FIG. 23 denote the equivalent portions, and thus description thereofis omitted. In the third specific example, identifiers of componentsshown in FIG. 25B are used as the information indicating schedulingcomponents. The carrier frequencies of components used in the basestation are associated with the identifiers of components (FIG. 25B). Asa specific example, the identifier of a component “CC #2” corresponds tothe information indicating the scheduling component 2302 of FIG. 25 .The identifier of a component “CC #4” corresponds to the informationindicating the scheduling component 2304 of FIG. 25 .

Differently from the first specific example in which values which areabsolute are mapped, and also differently from the second specificexample in which the identifies corresponding to the carrier frequenciesof components that can be taken by a mobile communication system aremapped, identifiers corresponding to the carrier frequencies ofcomponents that can be taken by the base station are mapped in the thirdspecific example. Therefore, an amount of information indicatingscheduling components, that is, an information bit number is smaller inthe third specific example. This achieves an effect that radio resourcesare effectively used.

The correspondence list of carrier frequencies of components andidentifiers of components, which is shown in FIG. 25B, is notified froma network to a UE. As a specific example of the notification method,notification is made from the base station to the UE by means of thebroadcast information, as a specific example, the BCCH (MIB or SIB). Theassociation is notified from the network to the UE, which achieves aneffect that an amount of information indicating scheduling componentscan be reduced while maintaining an advantage that a carrier frequencychange of a mobile communication system can be responded in a flexiblemanner.

As shown in FIG. 25C, the identifiers of components are used as theinformation indicating the scheduling components used for association ofcomponent indices and scheduling components.

A similar method to that of the first embodiment can be used as aspecific example of numbering of identifiers of components. Therefore,description thereof is omitted.

FIG. 26 is a conceptual diagram of association of the component indicesand scheduling components, which is performed in a component schedulingblock. Description is given with the use of, as a specific example, theidentifiers of components in the third specific example as theinformation indicating the scheduling components.

The scheduling components allocated to the UE 2308 at a time t1 in(1)-(a) are the CC #2 (2302) and a CC #4 (2304). The componentscheduling block associates the component index notified from a higherlayer with the scheduling component. A specific example there of isshown in FIG. 23 (1)-(b), where the component scheduling blockassociates a component index “CC_I #1” with the scheduling component CC#2 and a component index “CC_I #2” with the scheduling component CC #4.

The radio environment between a UE and a base station varies, and thescheduling components are changed in accordance with the CQI measured bya UE and measurement results.

The scheduling components allocated to the UE 2301 at a time t2 in(2)-(a) are the CC #4 (2304) and CC #5 (2305). The component schedulingblock associates the component index notified from a higher layer withthe scheduling component. A specific example thereof is shown in FIG. 23(2)-(b), where the component scheduling block associates the componentindex “CC_I #1” with the scheduling component CC #5 and the componentindex “CC_I #2” with the scheduling component CC #4.

That is, the component scheduling block changes the scheduling componentassociated with the component index CC_I #1 from CC #2 (time t1) to CC#5 (time t2). The higher layer that adds the component index to, forexample, an RRC message is not required to know that the schedulingcomponent allocated to the UE (2308) has been changed on the physicallayer.

FIG. 27 shows an example of the operation. As one example, descriptionis given by using the identifiers of components in the third specificexample as the information indicating the scheduling component. In FIG.27 , identical or equivalent process is performed in the steps of thesame reference numerals as those of FIG. 19 , and thus description ofthe steps of the same reference numerals is omitted.

In Step ST2701, a base station adds the information indicating acomponent index as an element in the RRC message being thecomponent-unit control information. For example, in the description bytaking FIG. 26 (1) as an example, the information of the component index“CC_I #1” is added as an element in the RRC message.

In Step ST2702, the base station judges whether or not the types ofcomponent indices have been added, deleted or updated. Alternatively,the base station judges whether or not to associate component indiceswith scheduling components again as a result of a change of componentindices. The base station moves to Step ST2704 in a case where the typesof component indices have been added, deleted or updated. The basestation moves to Step ST2703 in a case where the types of componentindices have not been added, deleted or updated.

In Step ST2703, the base station judges whether or not the schedulingcomponents have been added, deleted or updated. Alternatively, the basestation judges whether or not to associate component indices withscheduling components again as a result of a change of schedulingcomponents. The base station moves to Step ST2704 in a case where thetypes of scheduling components have been added, deleted or updated. Thebase station moves to Step ST1904 in a case where the types of componentindices have not been added, deleted or updated.

In Step ST2704, the base station associates the component indices withthe scheduling components.

In Step ST2705, the base station notifies the UE of the correspondencelist (for example, FIG. 26 (1)-(b)) that shows the results ofassociation of component indices and scheduling components (StepST2704). A specific example of the notification method is describedbelow.

It is conceivable that a notification is made from the base station tothe UE by a dedicated control signal. The scheduling components may bechanged as required in consideration of a radio environment per UE,which results in that unnecessary information is transmitted to theother UE by a common control signal and broadcast information.Accordingly, the radio resources are wasted. It is therefore possible toobtain an effect that radio resources are effectively used bynotification by a dedicated control signal.

The notification method in which a control delay is shorter comparedwith the RRC message is used for a dedicated control signal. Thisprevents a control delay from increasing as a mobile communicationsystem, which is a problem to be solved by the second solution of thethird embodiment.

It is conceivable that the PDCCH or MAC message is used as a specificexample of the dedicated control signal.

Specific examples of the notification method in a case of using thePDCCH are described below.

(1) Notification is made by means of the PDCCH of the component includedin a candidate component carrier set. The candidate component is acomponent capable of data transmission/reception between a base stationand a UE. Differently from the case where notification is made by meansof all components of the base station, this achieves an effect thatradio resources are effectively used and does not cause a problem thatthe UE cannot receive the notification due to the UE making anotification from the component capable of transmission/reception.Further, a UE is not required to monitor the PDCCH included in thecomponent other than the candidate component, leading to an effect ofless power consumption of a UE.

(2) Notification is made by means of the PDCCH of the component includedin scheduling components. The scheduling component is a component wheredata transmission/reception is practically performed. This achieves aneffect that radio resources are effectively used differently from thecase where notification is made by means of all components of the basestation, and achieves an effect that radio resources are used moreeffectively differently from the case where notification is made bymeans of a candidate component. Besides, this does not cause a problemthat the UE cannot receive the notification due to the UE making anotification from the component where data transmission/reception ispractically performed. Further, a UE is not required to monitor thePDCCH included in the component other than the scheduling component,leading to an effect of less power consumption of a UE.

(3) Notification is made by means of the PDCCH of the component includedin an anchor component during communication. The anchor component isdefined as a component for enabling the UE during communication tomonitor the PDCCH or the component for performing a measurement. In thatcase, the UE does not need to monitor the PDCCH included in thecomponent other than the anchor component, leading to an effect of lesspower consumption of a UE.

In Step ST2706, the UE receives the correspondence list that shows theresults of association of component indices and scheduling components(Step ST2704) from the base station.

In Step ST2707, the UE obtains the component index in the RRC message.In the description given by taking FIG. 26 (1) as an example, the UEobtains the component index “CC_I #1” as an element in the RRC message.

In Step ST2708, the UE obtains the component identifier of the componentcontrolled by the RRC message, based on the correspondence list (forexample, FIG. 26 (1)-(b)) that shows the results of association ofcomponent indices and scheduling components (Step ST2704) received inStep ST2706. For example, the UE obtains the identifier of a component“CC #2” of the scheduling component corresponding to the component index“CC_I #1” from FIG. 26 (1)-(b).

The third embodiment can be used in combination with the firstembodiment.

Alternatively, whether the solutions of the first embodiment are used orthe solutions of the third embodiment is used may be discriminateddepending on the control information in the RRC message or the contentsof control.

A specific example of discriminating solutions is described below.

(1) The second solution of the third embodiment in which scheduling ofcomponents can be quickly followed is used for the control informationrequired to quickly follow a change of scheduling components, whereasthe first solution of the first embodiment or third embodiment is usedfor the control information that is not required to quickly follow achange of scheduling components. As specific examples thereof, thesecond solution of the third embodiment may be used for “Radio resourceConfiguration”, whereas the first solution of the first embodiment orthird embodiment may be used for “Radio link failure related action” and“Measurement”.

(2) The first solution of the first embodiment or third embodiment inwhich a higher layer, as a specific example, a layer that controls anRRC message recognizes the scheduling results of components to a UE maybe used for the control information related to carrier frequency of acomponent or related to frequency characteristics. While, the secondsolution of the third embodiment may be used for the control informationirrelevant to carrier frequency of a component or irrelevant tofrequency characteristics.

This achieves an effect that the optimum RRC message notification methodcan be used depending on the control information in an RRC message orthe contents of control.

While the third embodiment has mainly described a downlink RRC message,the third embodiment is similarly applicable to an uplink RRC message.

In addition to the logical channels DCCH and CCCH, the logical channelMCCH and the logical channel BCCH are mapped to the transport channelDL-SCH by the control information. The third embodiment is similarlyapplicable to the MCCH and BCCH.

While the third embodiment has mainly described an RRC message, it isalso applicable to a MAC message.

In a case of application to a MAC message, in a base station supports tocarrier aggregation, it suffices that not the information indicating theMAC message is the control information corresponding to what component,but a component index is added to a MAC message, as an element in theMAC message, or in an area different from that for the MAC message, forexample, a header or footer. Detailed description is similar to that inthe case of RRC message and is accordingly omitted.

The third embodiment can achieve the following effects in addition tothe effects of the first embodiment and the second embodiment.

A higher layer does not need to recognize the scheduling results ofcomponents to a UE. This enables to follow the scheduling of componentsmore quickly compared with the first embodiment and the secondembodiment, and thus an effect of preventing a control delay in a mobilecommunication system can be achieved. That is, scheduling of componentscan be responded in a flexible manner.

Even in a case where the components scheduled to a UE may vary in ashort period of time, a problem as to whether the RRC message receivedby a receiver is the control information corresponding to what componentis unclear can be solved.

Fourth Embodiment

A problem to be solved by the fourth embodiment is described.

The use of the solutions of the third embodiment enable to solve aproblem as to whether the received RRC message is the controlinformation corresponding to what component is unclear is solved, evenin a case where a scheduling change of component carriers for a UE mayoccur in a short period of time. However, the third embodiment does notwork effectively unless the correspondence list, which shows the resultsof association of component indices and scheduling components, has beennotified from a transmitter to a receiver.

For example, in a case where the control information, as a specificexample, the RRC message or MAC message is notified from a transmitterto a receiver before the completion of notification of thecorrespondence list, there occurs a problem that the received controlinformation, as a specific example, the RRC message or MAC message isrecognized as the control information for an irrelevant component.

If the control information, as a specific example, the RRC message orMAC message is not notified until the completion of notification of thecorrespondence list for preventing the above-mentioned problem, aproblem of an increase in control delay occurs as a mobile communicationsystem.

A solution in the fourth embodiment is described below.

In a base station supports to carrier aggregation, the controlinformation corresponding to the components included in a candidatecomponent carrier set of a UE, as a specific example, the RRC message orMAC message is transmitted in advance to components included in thecandidate component carrier set.

A scheduling component including one or a plurality of components wheredata transmission/reception is practically performed is selected from acandidate component carrier set (candidate set) being a set of one or aplurality of component candidates capable of data transmission/receptionwith the UE. The selection is performed as a result of measurements of aUE, based on the CQI.

FIG. 28 is a conceptual diagram of the solution in the fourthembodiment. 2801 to 2807 denote downlink components capable of carrieraggregation in the base station. 2808 to 2812 denote uplink componentscapable of carrier aggregation in the base station. fD1 to fD10 denotecarrier frequencies of components of the respective downlink components.fU1 to fU9 denote carrier frequencies of components of the respectiveuplink components.

The components 2801 and 2808, 2802 and 2809, 2803 and 2810, and 2804 and2811 form a pair of downlink and uplink bands. 2805, 2806 and 2807 forman asymmetric pair of bands with 2812.

2813 denotes a scheduling component being a component where datatransmission/reception with a UE is practically performed. Thescheduling component 2813 includes the components 2801, 2802, 2808 and2809. 2814 denotes a candidate component carrier set capable oftransmitting/receiving data to/from a UE. The candidate carrier set 2814includes the components 2801, 2802, 2803, 2808, 2809 and 2810.

FIG. 29 shows an example of the operation.

In Step S2901, the UE transmits the measurement results on the receptionquality, CQI or the like to the base station.

In Step ST2902, the base station receives the measurement results on thereception quality, CQI or the like from the UE.

In Step ST2903, the base station judges whether or not a component to beadded to the component included in a candidate component carrier setcorresponding to the UE is present based on the measurement results of aUE or the CQI received in Step ST2902. In the case where there is acomponent to be added, the base station moves to Step ST2904. In thecase where there is no component to be added, the base station moves toStep ST2907. Alternatively/Further, in Step ST2903, the base stationjudges whether or not to newly create a candidate component carrier setfor the UE. In the case of newly creating one, the base station moves toStep ST2904. In the case of not newly creating one, the base station maymove to Step ST2907.

In Step ST2904, the base station reserves a radio resource for the UE inthe component to be added to the candidate component carrier set ifnecessary. Specific examples of the radio resource required to bereserved include a resource for a scheduling request.

In Step ST2905, the base station transmits the control informationrelated to a component to be added to the component included in thecandidate component carrier set, as a specific example, the RRC messageor MAC message. The first embodiment, the second embodiment includingmodifications or the third embodiment can be used as the solution to theproblem as to whether control information, as a specific example, theRRC message or MAC message is the control information corresponding towhat component is unclear. Thus, description thereof is omitted. Aspecific example of the method of notifying the correspondence list,which shows the results of association of the component indices andscheduling components in the third embodiment, can be used as thenotification method. Thus, description thereof is omitted.

There is another conceivable case where a base station notifies a UE ofa component to be added to the component included in a candidatecomponent carrier set. In that case, the control information related tothe component to be added to the component included in the candidatecomponent carrier set is transmitted together with the RRC message orMAC message. Note that the control information related to the componentto be added and the RRC message or MAC message may be transmittedsimultaneously or not.

In Step ST2906, the UE receives the control information related to thecomponent to be added to the component included in the candidatecomponent carrier set, as a specific example, the RRC message or MACmessage from the base station.

In Step ST2907, the base station judges whether or not to change thecomponent included in the scheduling components for the UE based on themeasurement results of a UE or CQI received in Step ST2902. The basestation moves to Step ST2908 in a case where a change is made. The basestation ends the process in a case where no change is made.

In Step ST2908, the base station notifies the UE of the componentsincluded in the scheduling components. The base station may notify theinformation related to all components included in the schedulingcomponents after change, or may notify the information related to thecomponent only for an amount of a difference between before and afterchange. In the case where the base station notifies the informationrelated to all components, an effect of greater resistance to radiocommunication error can be achieved. In addition, in the case where thebase station notifies the information related to the component for onlyamount of a difference between before and after change, an amount ofinformation to be notified can be reduced, leading to an effect thatradio resources are effectively used. The information “carrier frequencyof a component” and “identifier of a component” that indicate thecontrol information corresponding to what component in the firstembodiment can be used as a specific example of the information relatedto the component included in the scheduling components, and thusdetailed description thereof is omitted. The method of notifying thecorrespondence list that shows the results of association of thecomponent indices and scheduling components in the third embodiment canbe used as a specific example of the notification method, and thusdescription thereof is omitted.

In Step ST2909, the UE receives the information related to the componentincluded in the scheduling components from the base station.

In Step ST2910, the UE applies the control information received in StepST2906, as a specific example, the RRC message or MAC message to thecomponent included in the scheduling components.

The fourth embodiment can be used in combination with the firstembodiment, the second embodiment including modifications or the thirdembodiment.

Alternatively, whether the solutions of the first embodiment or thesecond embodiment are used, the solutions of the third embodiment areused, or the fourth embodiment is used may be discriminated depending onthe control information of the RRC message or MAC message, or thecontents of control.

A specific example of discriminating solutions is described below.

(1) As to the control information required to quickly follow a change ofscheduling component, the fourth embodiment or the second solution ofthe third embodiment, which enables component scheduling to be quicklyfollowed, may be used. Meanwhile, as to the control information that isnot required to quickly follow a change of scheduling component, thefirst solution of the first embodiment or third embodiment may be used.

(2) As to the control information related to carrier frequency of acomponent or frequency characteristics, the first embodiment or thefirst solution of the third embodiment in which a higher layer, as aspecific example, the layer that controls the RRC message obtains thescheduling results of a component for a UE may be used. Meanwhile, as tothe control information that is not related to carrier frequency of acomponent or frequency characteristics, the second solution of the thirdembodiment or the fourth embodiment may be used.

(3) As to the control information in which contents of control are notfrequently changed, the fourth embodiment may be used. Meanwhile, as tothe control information in which the contents of control are frequentlychanged, the third embodiment or the first embodiment may be used.

This achieves an effect that the method of notifying an optimum RRCmessage can be used depending on the control information of the RRCmessage or the contents of control.

The fourth embodiment can achieve the following effect in addition tothe effects of the first embodiment, second embodiment and thirdembodiment.

A scheduling component is selected from the components included in acandidate component carrier set, and the control informationcorresponding to the components included in a candidate componentcarrier set is notified from a transmitter to a receiver in advance.Accordingly, the fourth embodiment can achieve an effect that componentscheduling can be quickly followed.

It is not required for a transmitter to notify a receiver of acorrespondence list that shows the results of association of thecomponent indices and scheduling components, which is required in thethird embodiment. This solves a problem that in a case where, forexample, a transmitter notifies a receiver of the control information,as a specific example, the RRC message or MAC message until thecompletion of the notification of the correspondence list, the receivedcontrol information, as a specific example, the received RRC message orMAC message is recognized as the control information corresponding to anirrelevant component.

In addition, a problem of an increase in control delay as a mobilecommunication system can be solved because the notification of thecontrol information, as a specific example, the RRC message or MACmessage does not need to be held until the completion of notification ofthe correspondence list.

A specific effect in a case where the fourth embodiment is used for theRRC message, which is disclosed in Non-Patent Document 9, is describedbelow.

First, the control information corresponding to downlink is describedusing a specific example.

With the use of the fourth embodiment, the base station notifies inadvance the UE of the configuration information related to a radioresource corresponding to a component included in a candidate componentcarrier set, as a specific example, “Radio resource Configuration”, theconfiguration information related to a physical layer included in “Radioresource Configuration”, as a specific example, “Physical configDedicated”, the configuration information related to the PDSCH includedin “Physical config Dedicated” included in “Radio resourceConfiguration”, as a specific example, “pdsch-configdedicated”, or thetransmission power information of a reference signal included in“pdsch-configdedicated” included in “Physical config Dedicated” includedin “Radio resource Configuration”, as a specific example,“referenceSignalPower”.

Description is given with reference to FIG. 28 , where the controlinformation corresponding to the downlink components 2801, 2802 and 2803that are included in the candidate component carrier set 2814 isnotified in advance. Accordingly, even when the downlink schedulingcomponents are changed from 2801 and 2802 to 2802 and 2803 shown in FIG.28 , the UE recognizes the control information of 2803 in advance.

Therefore, the use of the fourth embodiment achieves an effect that a UEis capable of control using, for example, the configuration informationrelated to the PDSCH in 2803, as a specific example,“pdsch-configdedicated” immediately after 2803 is included in thescheduling components.

Further, “referenceSignal Power” is used as reference power of downlinktransmission power control. Therefore, the use of the fourth embodimentachieves an effect that downlink transmission power control is enabledusing the transmission power information of a reference signal in 2803,as a specific example, “referenceSignalPower” immediately after 2803 isincluded in the scheduling components.

Next, the control information corresponding to uplink is described witha specific example.

With the use of the fourth embodiment, the base station notifies inadvance the UE of the configuration information related to a radioresource corresponding to a component included in a candidate componentcarrier set, as a specific example, “Radio resource Configuration”, theconfiguration information related to a physical layer included in “Radioresource Configuration”, as a specific example, “Physical configDedicated”, the configuration information related to the PUSCH includedin “Physical config Dedicated” included in “Radio resourceConfiguration”, as a specific example, “pusch-configdedicted”, or thecontrol information related to hopping included in“pusch-configdedicated” included in Physical config Dedicated” includedin “Radio resource Configuration”, as a specific example, “hoppingMode”and “pusch-hopping Offset”. Description is given with reference to FIG.28 , where the control information corresponding to the uplinkcomponents 2808, 2809 and 2810 that are included in the candidatecomponent carrier set 2814 is notified in advance. Accordingly, evenwhen the uplink scheduling components are changed from 2808 and 2809 to2809 and 2810 shown in FIG. 28 , the UE recognizes the controlinformation of 2810 in advance.

Therefore, the use of the fourth embodiment achieves an effect that a UEis capable of control using the configuration information related to thePUSCH in 2810, as a specific example, “pusch-configdedicated”immediately after 2810 is included in the scheduling components.

The control information related to hopping cannot be accurately receivedunless a UE being a transmitter and a base station being a receiverperform transmission/reception by sharing the same recognition. Inaddition, hopping is introduced for alleviating an effect of frequencyphasing.

Therefore, the use of the fourth embodiment achieves an effect thathopping control is enabled with the use of the control informationrelated to hopping in 2810 immediately after 2810 is included in thescheduling components. This enables the transmission of the PUSCH usinghopping in 2810 immediately after 2810 is included in the schedulingcomponents, leading to an effect that the transmission of PUSCHresistant to frequency phasing is enabled. This leads to an effect thatradio resources are effectively used.

With the use of the fourth embodiment, the base station notifies inadvance the UE of the configuration information related to a radioresource corresponding to a component included in a candidate componentcarrier set, as a specific example, “Radio resource Configuration”, theconfiguration information related to a physical layer included in “Radioresource Configuration”, as a specific example, “Physical configDedicated”, or the configuration information related to the PUCCHincluded in “Physical config Dedicated” included in “Radio resourceConfiguration”, as a specific example, “pucch-configdediated”.

Description is given with reference to FIG. 28 , where the controlinformation corresponding to the uplink components 2808, 2809 and 2810that are included in the candidate component carrier set 2814 isnotified in advance. Accordingly, even when the uplink schedulingcomponents are changed from 2808 and 2809 to 2809 and 2810 shown in FIG.28 , the UE recognizes the control information of 2810 in advance.

Therefore, the use of the fourth embodiment achieves an effect that a UEis capable of control using the configuration information related to thePUCCH in 2810, as a specific example, “pucch-configdedicated”immediately after 2810 is included in the scheduling components.

With the use of the fourth embodiment, the base station notifies inadvance the UE of the configuration information related to a radioresource corresponding to a component included in a candidate componentcarrier set, as a specific example, “Radio resource Configuration”, theconfiguration information related to a physical layer included in “Radioresource Configuration”, as a specific example, “Physical configDedicated”, the configuration information related to a schedulingrequest included in “Physical config Dedicated” included in “Radioresource Configuration”, as a specific example,“schedulingRequestconfig”, or the resource information related to ascheduling request included in “schedulingRequestconfig” included in“Physical config Dedicated”, as a specific example,“sr-PUCCH-ResoruceIndex”.

Description is given with reference to FIG. 28 , where the controlinformation corresponding to the uplink components 2808, 2809 and 2810that are included in the candidate component carrier set 2814 isnotified in advance. Accordingly, even when the uplink schedulingcomponents are changed from 2808 and 2809 to 2809 and 2810 shown in FIG.28 , the UE recognizes the control information of 2810 in advance.

The scheduling request is a signal for requesting uplink resourceallocation to a base station by a UE. In a case where the UE requestsuplink resource allocation, when allocation is not performed for the UEin response to the scheduling request, the UE is required to requestuplink resource allocation by means of the RACH. In the uplink resourceallocation request by means of the RACH, a control delay is increasedcompared with the uplink resource allocation request using a schedulingrequest.

Therefore, the use of the fourth embodiment enables to achieve an effectthat the UE can perform control with the use of the configurationinformation related to a scheduling request in 2810, as a specificexample, “schedulingRequest config” immediately after 2810 is includedin the scheduling components. Along with this, the UE is capable ofrequesting uplink resource allocation using a scheduling request in 2803immediately after being included in the scheduling component, achievingan effect that an increase in control delay can be prevented.

While the fourth embodiment has mainly described the downlink RRCmessage, the fourth embodiment is also applicable to the downlink MACmessage, uplink RRC message and uplink MAC message.

In addition to the logical channels DCCH and CCCH, the logical channelMCCH and logical channel BCCH are mapped to the transport channel DL-SCHas the control information. The fourth embodiment is similarlyapplicable to the MCCH and BCCH.

First Modification of Fourth Embodiment

A problem to be solved in a first modification of the fourth embodimentis described.

In a case of using the solution of the fourth embodiment, in some cases,the component to be added to a candidate component carrier set needs toreserve a radio resource for the UE. In this case, at times, a radioresource for the UE is reserved also in the component where datatransmission/reception is not practically performed between the UE andthe base station. This causes a problem that radio resources are wasted.

Further, the UE is required to store the control informationcorresponding to the components included in the candidate componentcarrier set. The UE needs to reserve a large storage area for controlinformation along with an increase of the components included in thecandidate component carrier set, causing a problem of an increase inhardware of a UE, for example, memory and CPU or an increase in load ofsoftware of the UE.

The solution in the first modification of the fourth embodiment isdescribed below.

An upper limit is provided to the number of components that can beincluded in a candidate component carrier set in the base station whichsupports to carrier aggregation. An example of the operation is shown inFIG. 30 . The same reference symbols as those of FIG. 29 denoteequivalent portions, and thus description thereof is omitted.

In Step ST3001, the base station judges whether or not it is required tochange the candidate component carrier set corresponding to the UE basedon the measurement results of the UE or CQI received in Step ST2902. Inthe case where a change is required, the base station moves to StepST3002. In the case where a change is not required, the base stationmoves to Step ST2907.

The candidate component carrier sets may be provided separately foruplink and downlink. In the case where those are provided separately,the judgment of Step ST3001 may be performed separately for uplink anddownlink. Alternatively/Further, in Step ST3001, the base station judgeswhether or not to newly create a candidate component carrier set for theUE. In the case of newly creating one, the base station moves to StepST3003. In the case of not newly creasing one, the base station may moveto Step ST2907.

In Step ST3002, the base station judges whether or not there is acomponent to be added to the components included in a candidatecomponent carrier set based on the measurement results of a UE or CQIreceived in Step ST2902. In the case where there is a component to beadded, the base station moves to Step ST3003. In the case where there isno component to be added, the base station moves to Step ST3006.

In Step ST3003, the base station judges whether or not the number ofcomponents included in the current candidate component carrier set isequal to or larger than the upper limit of the number of components thatcan be included in the candidate component carrier set. In the casewhere the number is equal to or larger than the upper limit, the basestation moves to Step ST3004. In the case where the number is not equalto or larger than the upper limit, the base station moves to StepST3005.

The upper limit may be determined in a static manner as a mobilecommunication system, may be determined in a static manner orsemi-static manner per base station which supports to carrieraggregation, or may be determined in accordance with the capability of aUE. In the case where the upper limit is determined in accordance withthe capability of a UE, the UE may notify the base station of the numberof components that can be subjected to carrier aggregation, or a UEitself may determine an upper limit in accordance with the capability ofa UE to notify the base station of the upper limit. In the case where anupper limit is determined in a static manner as a mobile communicationsystem and in the case where an upper limit is determined in accordancewith the capability of a UE, an upper limit can be provided to hardwareor software in designing of a UE, leading to an effect that a UE isprevented from becoming complicated. In the case where an upper limit isdetermined in a static manner or semi-static manner per base stationsupports to carrier aggregation, the control can be performed inaccordance with, for example, a load status of a radio resource of abase station, leading to an effect that a mobile communication systemcan be constructed flexibly. Conceivable specific examples of thecapability of a UE include the size of a storage area (such as memory)for control information, a compliant release number and a compliantcommunication speed.

In Step ST3004, the base station adds a new component to the candidatecomponent carrier set corresponding to the UE based on the measurementresults of the UE or CQI received in Step ST2902, and deletes thecomponent included in the candidate component carrier set. That is, thebase station updates the component included in the candidate componentcarrier set.

In Step ST3005, the base station adds a new component to the candidatecomponent carrier set corresponding to the UE based on the measurementresults of the UE or CQI received in Step ST2902.

In Step ST3006, the base station deletes the component included in thecandidate component carrier set corresponding to the UE based on themeasurement results of the UE or CQI received in Step ST2902.

In Step ST3007, the base station notifies the UE of the componentsincluded in the candidate component carrier set. The base station maynotify the information related to all components included in thecandidate component after changing, or may notify the informationrelated to the component for only an amount of a difference betweenbefore and after change. In the case where the information related toall components is notified, an effect of greater resistance to a radiocommunication error can be achieved. Alternatively, in the case wherethe information related to the component for only an amount of adifference between before and after change is notified, an amount ofinformation to be notified can be reduced, leading to an effect thatradio resources are effectively used. A specific example of thecorrespondence list, which shows results of association of the componentindices and scheduling components in the third embodiment, can be usedas the notification method. Therefore, description thereof is omitted.

In Step ST3008, the UE receives the components included in the candidatecomponent carrier set from the base station.

The first modification of the fourth embodiment can be used incombination with the first embodiment, the second embodiment includingmodifications or the third embodiment.

Alternatively, whether the solutions of the first embodiment or thesecond embodiment, the solutions of the third embodiment or the firstmodification of the fourth embodiment is used may be discriminateddepending on the control information of the RRC message or MAC message,or the contents of control. A specific example for discriminating thesolutions is similar to that of the fourth embodiment, and thusdescription thereof is omitted.

In addition to the effects of the first embodiment, second embodiment,third embodiment and fourth embodiment, the following effects can beachieved by the first modification of the fourth embodiment.

An upper limit number of components included in a candidate componentcarrier set is determined, whereby it is possible to provide an upperlimit to reserving of a radio resource for the UE in the component wheredata transmission/reception is not practically performed between the UEand the base station. This achieves an effect that radio resources areeffectively used.

Further, an upper limit number of components included in the candidatecomponent carrier set is determined, whereby the UE can provide an upperlimit to the storage area for control information corresponding to thecomponents included in the candidate component carrier set. This enablesto provide an upper limit to hardware or software in designing of a UE,leading to an effect that the UE can be prevented from becomingcomplicated.

Second Modification of Fourth Embodiment

A problem to be solved by a second modification of the fourth embodimentis similar to that of the fourth embodiment, and thus descriptionthereof is omitted.

A solution in the second modification of the fourth embodiment isdescribed below.

In a base station supports to carrier aggregation, the controlinformation corresponding to components included in a candidatecomponent carrier set of a UE, as a specific example, the RRC message orMAC message is made common to the components included in the candidatecomponent carrier set.

An example of the operation is similar to that of the fourth embodiment.Only a different portion is described with reference to FIG. 29 .

In Step ST2904, the base station reserves a similar radio resource tothat of the components included in the candidate component carrier setfor the UE, in the component to be added to the candidate componentcarrier set. Specific examples of the radio resource to be reservedinclude a resource for a scheduling request.

The control information is common to the components included in thecandidate component carrier set, and thus Step ST 2905 and Step ST2906are not required. In the case where a candidate component carrier set isnewly created for the UE, the base station transmits the controlinformation related to a component to be added to the componentsincluded in the candidate component carrier set, as a specific example,the RRC message or MAC message.

The second modification of the fourth embodiment and the firstmodification of the fourth embodiment can be used in combination.

An example of the operation is similar to that of the first modificationof the fourth embodiment. Only a different portion is described withreference to FIG. 30 .

In Step ST2904, the base station reserves a similar radio resource tothat of the components included in the candidate component carrier setfor the UE, in the component to be added to the candidate componentcarrier set. Further, the base station makes open the radio resource forthe UE in the component to be deleted from the candidate componentcarrier set. Specific examples of the radio resource required to bereserved include a resource for a scheduling request.

The second modification of the fourth embodiment can be used incombination with the first embodiment, the second embodiment includingmodification or the third embodiment.

Alternatively, whether the solutions of the first embodiment or thesecond embodiment, the solutions of the third embodiment or the secondmodification of the fourth embodiment is used may be discriminateddepending on the control information of the RRC message or MAC message,or depending on the contents of control. A specific example fordiscriminating the solutions is similar to that of the fourthembodiment, and thus description thereof is omitted.

In addition to the effects of the first embodiment, second embodiment,third embodiment and fourth embodiment, the following effect can beachieved by the first modification of the fourth embodiment.

The control information for the components included in the candidatecomponent carrier set of a UE is common to the components included inthe candidate component carrier set, whereby it is possible to reducethe storage area for control information in the UE. This enables toreduce hardware or software in designing of a UE, leading to an effectthat the UE can be prevented from becoming complicated.

Third Modification of Fourth Embodiment

A problem to be solved by a third modification of the fourth embodimentis described.

In the case where the solution of the fourth embodiment or the thirdmodification of the fourth embodiment is used, in some cases, it isnecessary to secure a radio resource for the UE in the component to beadded to the candidate component carrier set. In this case, also in thecomponent where data transmission/reception is not practically performedbetween a UE and a base station, the radio resource for the UE issecured at times. This causes a problem that radio resources are wasted.

A solution in the third modification of the fourth embodiment isdescried below.

In a base station supports to carrier aggregation, a radio resource fora UE is reserved for a part of the components included in the candidatecomponent carrier set or for a single component only. Alternatively, aradio resource for a UE is reserved for a part of the componentsincluded in the scheduling components or for a single component only.

Specific examples of the radio resource reserved for a UE in a basestation supports to carrier aggregation include a resource for ascheduling request.

An anchor component is a specific example of a part of the components orone component included in a candidate component carrier set or a part ofthe components or one component included in the scheduling components.

In other words, in a base station supports to carrier aggregation, thecomponent where a scheduling request is transmitted from a UE to a basestation is a part of the components or a single component only includedin the candidate component carrier set or a part of the components or asingle component only included in the scheduling components.

The third modification of the fourth embodiment can be used incombination with the first embodiment, second embodiment includingmodifications, third embodiment or fourth embodiment includingmodifications.

The third modification of the fourth embodiment can achieve thefollowing effect.

It is possible to reduce reserving of a radio resource for the UE in acomponent where data transmission/reception is not practically performedbetween a UE and a base station. This achieves an effect that radioresources can be effectively used.

Fifth Embodiment

A problem to be solved by a fifth embodiment is described.

As described in the first embodiment, carrier aggregation in receptionand transmission on a plurality of component carriers, in reception onlyor in transmission only is supported in the LTE-A system.

As a specific example of the measurement required for a UE in performingcarrier aggregation, 3GPP has discussed the following in a meeting(Non-Patent Document 14).

In order to support different coverages, there is a need to comparemeasurement objects on the same frequency with a configured componentcarrier. For the sake of convenience, this measurement is referred to asthe first measurement. The first measurement can be used to know thebest cell in a UE on a given frequency.

A specific example is shown in FIG. 31 . Suppose a case where aconfigured component carrier 1 (configured CC_1) 3101, a configuredcomponent carrier 2 (configured CC_2) 3102 and a configured componentcarrier 3 (CC_3) 3103 are present as the component carriers configuredfor a UE in a serving base station 3104 of the UE. In addition, supposea case where a component carrier 1 (neighboring base station_CC_1) 3105,a component carrier 2 (neighboring base station_CC_2) 3106 and acomponent carrier 3 (neighboring base station_CC_3) 3107 are present ina neighboring base station 3108 of the UE. The configured CC_1 and theneighboring base station_CC_1 are present on the same frequency layer3109 (f1). The configured CC_2 and the neighboring base station_CC_2 arepresent on the same frequency layer 3110 (f2). The configured CC_3 andthe neighboring base station_CC_3 are present on the same frequencylayer 3111 (f). In the first measurement, the measurement objects on thesame frequency are compared with the configured component carrier.Specifically, the UE performs measurement of comparing the configuredCC_1 being the configured component carrier and the neighboring basestation_CC_1 present on the same frequency f1. The UE performsmeasurement of comparing the configured CC_2 being the configuredcomponent carrier and the neighboring base station_CC_2 present on thesame frequency f2. The UE performs measurement of comparing theconfigured CC_3 being the configured component carrier and theneighboring base station_CC_3 present on the same frequency B.

It is required to compare the configured component carrier with acomponent carrier on a different frequency for supportinginter-base-station handover, inter-frequency handover and inter-systemhandover. For the sake of convenience, this measurement is referred toas the second measurement. A specific example is shown in FIG. 32 .

The specific example is shown in FIG. 32 . Suppose a case where aconfigured component carrier (configured CC_1) 3201 and a configuredcomponent carrier 2 (configured CC_2) 3202 are present as componentcarriers configured for a UE in a serving base station 3203 of the UE.In addition, suppose a case where a component carrier 1 (neighboringbase station_CC_1) 3204, a component carrier 2 (neighboring basestation_CC_2) 3205 and a component carrier 3 (neighboring basestation_CC_3) 3206 are present in a neighboring base station 3207 of theUE. The configured CC_1 and the neighboring base station_CC_1 arepresent on the same frequency layer 3208 (f1). The configured CC_2 andthe neighboring base station_CC_2 are present on the same frequencylayer 3209 (f2). The neighboring base station_CC_3 is present on thesame frequency layer 3110 (f3). In the second measurement, measurementobjects on a different frequency from that of the configured componentcarrier are compared. Specifically, the UE performs measurement ofcomparing the configured CC_2 being a configured component carrier onthe frequency f2 and the neighboring base station_CC_3 present on thefrequency f3 different from the frequency f2.

As to carrier aggregation, how to identify a measurement referencecomponent carrier in a case where a plurality of component carrier areconfigured is discussed. The following is described as specific methods(Non-Patent Document 14).

In the first method, the measurement reference component carrier isconfigured by a network. No change is made without reconfiguration bythe network. The component carrier is also referred to as a primarycomponent carrier (PCC).

In the second method, the measurement reference component carrier isconfigured per measurement identity by a network. The measurementidentity is described below in detail. However, specific configurationmethod is not disclosed.

In the third method, the measurement reference component carrier is madethe best component carrier within the UE. This is autonomously updatedby the UE and can be changed without reconfiguration by a network.

The following has been determined as to measurement in the currentspecifications of 3GPP (Non-Patent Document 15).

The network specifies a single E-UTRA carrier frequency as a measurementobject for a UE. There is a list of measurement objects.

The network specifics reporting criterion, reporting format and the likethat trigger the UE to transmit a measurement report by reportingconfigurations. The reporting format includes the number of cells toreport. In addition, there is a list of reporting configurations.

The network links one measurement object with one reportingconfiguration by a measurement identity for a UE and specifies those.There is a list of measurement identities.

The UE provides a measurement report to the network. The measurementreport includes the measurement identity that triggered the measurementreport to be transmitted, the PCI of a neighboring cell, and themeasurement results of a serving base station.

The UE manages one list of measurement objects, one list of reportingconfigurations and one list of measurement identities.

In the case of component carriers of the same base station, carrieraggregation of a different number of component carriers is supportedbetween uplink and downlink (Non-Patent Document 16). For the sake ofconvenience, the above-mentioned carrier aggregation is referred to asasymmetric carrier aggregation.

Suppose a case where asymmetric carrier aggregation is performed. Thecase of FIG. 33 is described as an example. The same reference symbolsas those of FIG. 31 denote equivalent portions, and thus descriptionthereof is omitted.

Suppose a case where a configured downlink component carrier (configuredDL_CC_1) 3301 and a configured downlink component carrier 2 (configuredDL_CC_2) 3302 are present as downlink component carriers configured fora UE in a serving base station 3308 of the UE. In addition, suppose acase where a configured uplink component carrier 2 (configured UL_CC_2)3306 is present as the uplink component carrier set in the UE.

The configured DL_CC_1 and the neighboring base station_CC_1 are presenton the same frequency layer 3303 (f1_DL). The configured DL_CC_2 and theneighboring base station_CC_2 are present on the same frequency layer3304 (f2_DL). A configured DL_CC_3 and the neighboring base station_CC_3are present on the same frequency layer 3305 (f3_DL). The configuredUL_CC_2 is present on a frequency layer 3307 (f2_UL).

That is, the UE aggregates two component carriers on a receiver side anduses one uplink component carrier on a transmitter side. Therefore, theUE performs asymmetric carrier aggregation.

A problem to be solved by the fifth embodiment is described withreference to FIG. 33 .

The case where the above-mentioned second measurement is performed isdiscussed with reference to FIG. 33 . The UE compares the configuredcomponent carrier with a measurement object on a different frequency.Specifically, the UE performs measurement of comparing the configuredDL_CC_1 being the configured downlink component carrier with theneighboring base station_CC_2 present on the different frequency f2_DL.For the sake of convenience, this is referred to as DL_CC_1 comparisonmeasurement. Further, the UE performs measurement of comparing theconfigured DL_CC_2 being the configured downlink component carrier withthe neighboring base station_CC_3 present on the different frequencyf3_DL. For the sake of convenience, this is referred to as DL_CC_2comparison measurement.

The UE is required to perform the above-mentioned two measurements tothe network and provide measurement reports related to the DL_CC_1comparison measurement and DL_CC_2 comparison measurement on one uplinkcomponent carrier (configured UL_CC_2). That is, the UE needs to notifythe network of the comparison results of the configured DL_CC_1 andconfigured DL_CC_2 being two different measurement reference componentcarriers, on one uplink component carrier.

Accordingly, in a case where asymmetric carrier aggregation isperformed, the network has no way to know a measurement referencecomponent carrier even when the UE provides a measurement report to thenetwork.

This causes a problem that mobility management such as handover andcomponent carrier management such as addition, deletion or switch ofcomponent carriers cannot be performed properly as a mobilecommunication system.

Non-Patent Document 14, Non-Patent Document 15 and Non-Patent Document16 do not point out this problem.

The above-mentioned problem arises even in a case where the method ofNon-Patent Document 14 as to how to identify a measurement referencecomponent carrier is applied.

In the LTE system, carrier aggregation is not supported. That is, uplinkand downlink have one-to-one relation. Therefore, in a case where the UEprovides a measurement report to the network, it is possible toimplicitly show that the frequency of a measurement reference componentcarrier is the downlink carrier frequency of a pair with an uplinkcarrier frequency on which a measurement report is provided. Inasymmetric carrier aggregation supported in the LTE-A system, on theother hand, the uplink and downlink do not have one-to-one relation, andthus the conventional method of implicitly showing a measurementreference cannot be used.

In the current specifications, the UE allows the measurement report forthe network to include the measurement identity that triggered thetransmission of a measurement report, the PCI of a neighboring cell, andthe measurement results of a serving cell. The UE manages one list ofmeasurement objects, one list of reporting configurations and one listof measurement identities. As described above, in the currentspecifications, the network that has received a measurement report inasymmetric carrier aggregation has no way to recognize a measurementreference component carrier.

As described above, the problem of the fifth embodiment does not arisein the LTE system, but a new problem arises in the system for supportingcarrier aggregation, as a specific example, LTE-A system.

A solution in the fifth embodiment is described below.

A UE allows the measurement report to include the information of ameasurement reference component carrier. Simultaneously, the UE mayallow the measurement report to include the measurement identity thattriggered the transmission of a measurement report, the PCI of aneighboring cell, and the measurement results of a serving cell, as inthe conventional technique. The network performs mobility management,component carrier management or the like based on the measurementreport. Specific examples of the entity of the network include a basestation.

As specific examples of the types of measurement reference componentcarriers, five examples are disclosed below.

(1) A cell that has the best reception quality in a UE (best cell). Thebest cell may be selected from the configured component carriers.Alternatively, the best cell may be selected from scheduling componentcarriers. Still alternatively, the best cell may be selected from acandidate component carrier set.

(2) A cell that has the worst reception quality in a UE (worst cell).The worst cell may be selected from the configured component carriers.Alternatively, the worst cell may be selected from scheduling componentcarriers. Still alternatively, the worst cell may be selected from acandidate component carrier set.

(3) A configured component carrier corresponding to a measurementobject. A configured component carrier on a carrier frequency specifiedby the measurement object. Non-Patent Document 17 proposes that thecomponent carrier is referred to as a serving cell. Alternatively, itmay be a scheduling component carrier on a carrier frequency specifiedby a measurement object. Still alternatively, it may be a candidatecomponent carrier on a carrier frequency specified by a measurementobject.

(4) A downlink component carrier where measurement configuration hasbeen made.

(5) A measurement reference component carrier configured from a networkto a UE. The information on one measurement reference component carrieris newly provided for a measurement configuration. The information on ameasurement reference component carrier may be newly provided within ameasurement object.

The following two examples are disclosed as specific examples of theinformation of a measurement reference component carrier. (1) A specificexample of the “information indicating the control informationcorresponding to what component” of the first embodiment can be used.(2) PCI. Non-Patent Document 18 proposes that different PCIs areallocated even to the component carriers belonging to the same basestation.

A UE may change the type of a measurement reference component carrierincluded in a measurement report per measurement configuration ormeasurement report triggering. The combination may be determined in amobile communication system in a semi-static manner or in a staticmanner.

The following two examples are disclosed as specific examples of theconfiguration method in a case where determination is made in asemi-static manner. (1) Notification is made by means of the broadcastinformation. (2) Notification is made by a measurement configuration.The information indicating the combination of measurement reporttriggering and measurement reference component carrier type is newlyprovided in the measurement configuration. The information indicating ameasurement reference component carrier type may be newly provided inthe measurement configuration per measurement report triggering.

Conventional measurement report triggering, which is disclosed inNon-Patent Document 15, is described.

An event A1 refers to a fact that the reception quality of a servingcell becomes better than a threshold. Specifically, the condition forthe event A1 to be satisfied is obtained when Expression (A1-1) below isfulfilled, while the condition for the event A1 to be satisfied is lostwhen Expression (A1-2) below is fulfilled.

Ms−Hys>Thresh  Expression (A1-1)

The condition for the event A1 to be satisfied is obtained when a valueobtained by subtracting a hysteresis value (Hys) from the receptionquality (Ms, which is RSRP, RSRQ or the like) of the serving cellbecomes better than the threshold (Thresh).

Ms+Hys<Thresh  Expression (A1-2)

The condition for the event A1 to be satisfied is lost when a valueobtained by adding the hysteresis value (Hys) to the reception quality(Ms) of the serving cell becomes worse than the threshold (Thresh).

An event A2 refers to a fact that the reception quality of the servingcell becomes worse than a threshold. Specifically, the condition for theevent A2 to be satisfied is obtained when Expression (A2-1) below isfulfilled, while the condition for the event A2 to be satisfied is lostwhen Expression (A2-2) below is satisfied.

Ms+Hys<Thresh  Expression (A2-1)

The condition for the event A2 to be satisfied is obtained when a valueobtained by adding the hysteresis value (Hys) to the reception quality(Ms) of the serving cell becomes worse than the threshold (Thresh).

Ms−Hys>Thresh  Expression (A2-2)

The condition for the event A2 to be satisfied is lost when a valueobtained by subtracting the hysteresis value (Hys) from the receptionquality (Ms) of the serving cell becomes better than the threshold(Thresh).

An event A3 refers to a fact that the reception quality of a neighboringcell becomes better than the reception quality of the serving cell.Specifically, the condition for the event A3 to be satisfied is obtainedwhen Expression (A3-1) below is fulfilled, while the condition for theevent A3 to be satisfied is lost when Expression (A3-2) below isfulfilled.

Mn+Ofn+Ocn−Hys>Ms+Ofs+Ocn+Off  Expression (A3-1)

The condition for the event A3 to be satisfied is obtained when a valueobtained by adding a frequency specific offset value (Ofn) of aneighboring cell to the reception quality (Mn) of the neighboring cell,adding a cell specific offset value (Ocn) of the neighboring cellthereto and subtracting a hysteresis value (Hys) therefrom becomesbetter than a value obtained by adding a frequency specific offset value(Ofs) of the serving cell to the reception quality (Ms) of the servingcell, adding a cell specific offset value (Ocs) of the serving cellthereto and adding an offset value (Off) of this event thereto.

Mn+Ofn+Ocn+Hys<Ms+Ofs+Ocn+Off  Expression (A3-2)

Meanwhile, the condition for the event A3 to be satisfied is lost when avalue obtained by adding the frequency specific offset value (Ofn) of aneighboring cell to the reception quality (Mn) of the neighboring cell,adding the cell specific offset value (Ocn) of the neighboring cellthereto and adding the hysteresis value (Hys) thereto becomes worse thana value obtained by adding the frequency specific offset value (Ofs) ofthe serving cell to the reception quality (Ms) of the serving cell,adding the cell specific offset value (Ocs) of the serving cell theretoand adding the offset value (Off) of this event thereto.

An event A4 refers to a fact that the reception quality of a neighboringcell becomes better than a threshold. Specifically, the condition forthe event A4 to be satisfied is obtained when Expression (A4-1) below isfulfilled, while the condition for the event A4 to be satisfied is lostwhen Expression (A4-2) below is fulfilled.

Mn+Ofn+Ocn−Hys>Thresh  Expression (A4-1)

The condition for the event A4 to be satisfied is obtained when a valueobtained by adding the frequency specific offset value (Ofn) of theneighboring cell to the reception quality (Mn) of the neighboring cell,adding the cell specific offset value (Ocn) of the neighboring cellthereto and subtracting the hysteresis value (Hys) therefrom becomesbetter than a threshold (Thresh).

Mn+Ofn+Ocn+Hys<Thresh  Expression (A4-2)

Meanwhile, the condition for the event A4 to be satisfied is lost when avalue obtained by adding the frequency specific offset value (Ofn) ofthe neighboring cell to the reception quality (Mn) of the neighboringcell, adding the cell specific offset value (Ocn) of the neighboringcell thereto and adding the hysteresis value (Hys) thereto becomes worsethan the threshold (Thresh).

An event A5 refers to a fact that the reception quality of the servingcell becomes worse than a threshold 1 and that the reception quality ofthe neighboring cell becomes better than a threshold 2. Specifically,the condition for the event A5 to be satisfied is obtained whenExpression (A5-1) and Expression (A5-2) below are fulfilled, while thecondition for the event A5 to be satisfied is lost when Expression(A5-3) or expression (A5-4) below is fulfilled.

Ms+Hys<Thresh1  Expression (A5-1)

The condition for Expression (A5-1) to be satisfied is obtained when avalue obtained by adding the hysteresis value (Hys) to the receptionquality (Ms) of the serving cell becomes worse than the threshold 1(Thresh1).

Mn+Ofn+Ocn−Hys>Thresh2  Expression (A5-2)

The condition for Expression (A5-2) to be satisfied is obtained when avalue obtained by adding the frequency specific offset value (Ofn) ofthe neighboring cell to the reception quality (Mn) of the neighboringcell, adding the cell specific offset value (Ocn) of the neighboringcell thereto and subtracting the hysteresis value (Hys) therefrombecomes better than the threshold 2 (Thresh2).

Ms−Hys>Thresh1  Expression (A5-3)

The condition for the event A5 to be satisfied is lost when a valueobtained by subtracting the hysteresis value (Hys) from the receptionquality (Ms) of the serving cell becomes better than the threshold 1(Thresh1).

Mn+Ofn+Ocn+Hys<Thresh2  Expression (A5-4)

The condition for the event A5 to be satisfied is lost when a valueobtained by adding the frequency specific offset value (Ofn) of theneighboring cell to the reception quality (Mn) of the neighboring cell,adding the cell specific offset value (Ocn) of the neighboring cellthereto and adding the hysteresis value (Hys) thereto becomes worse thanthe threshold 2 (Thresh2).

An event B1 refers to a fact that the reception quality of a neighboringcell in a different system becomes better than a threshold. Conceivableexamples of a different system include UTRA and CDMA2000. Specifically,the condition for the event B1 to be satisfied is obtained whenExpression (B1-1) below is fulfilled, while the condition for the eventB1 to be satisfied is lost when Expression (B1-2) below is fulfilled.

Mn+Ofn−Hys>Thresh  Expression (B1-1)

The condition for the event B1 to be satisfied is obtained when a valueobtained by adding the frequency specific offset value (Ofn) of theneighboring cell to the reception quality (Mn) of the neighboring cellin UTRA or CDMA2000 being a different system and subtracting thehysteresis value (Hys) therefrom becomes better than the threshold(Thresh).

Mn+Ofn+Hys>Thresh  Expression (B1-2)

The condition for the event B1 to be satisfied is lost when a valueobtained by adding the frequency specific offset value (Ofn) of theneighboring cell to the reception quality (Mn) of the neighboring cellin UTRA or CDMA2000 being a different system and adding the hysteresisvalue (Hys) thereto becomes worse than the threshold (Thresh).

An event B2 refers to a fact that the reception quality of the servingcell becomes worse than the threshold 1 and that the reception qualityof the neighboring cell in a different system becomes better than thethreshold 2. Conceivable examples of a different system include UTRA andCDMA2000. Specifically, the condition for the event B2 to be satisfiedis obtained when Expression (B2-1) and Expression (B2-2) below arefulfilled, while the condition for the event B2 to be satisfied is lostwhen Expression (B2-3) or Expression (B2-4) below is fulfilled.

Ms+Hys<Thresh1  Expression (B2-1)

The condition for Expression (B2-1) to be satisfied is obtained when avalue obtained by adding the hysteresis value (Hys) to the receptionquality (Ms) of the serving cell becomes worse than the threshold 1(Thresh1).

Mn+Ofn−Hys>Thresh2  Expression (B2-2)

The condition for Expression (B2-2) to be satisfied is obtained when avalue obtained by adding the frequency specific offset value (Ofn) ofthe neighboring cell to the reception quality (Mn) of the neighboringcell of UTRA or CDMA2000 being a different system and subtracting thehysteresis value (Hys) therefrom becomes better than the threshold 2(Thresh2).

Ms−Hys>Thresh1  Expression (B2-3)

The condition for the event B2 to be satisfied is lost when a valueobtained by subtracting the hysteresis value (Hys) from the receptionquality (Ms) of the serving cell becomes better than the threshold 1(Thresh1).

Mn+Ofn+Hys<Thresh2  Expression (B2-4)

The condition for the event B2 to be satisfied is lost when a valueobtained by adding the frequency specific offset value (Ofn) of theneighboring cell to the reception quality (Mn) of the neighboring cellin UTRA or CDMA2000 being a different system and adding the hysteresisvalue (Hys) thereto becomes worse than the threshold 2 (Thresh2).

An event A3-bis disclosed in Non-Patent Document 14 refers to a factthat the reception quality of the neighboring cell on a frequencydifferent from that of the serving cell becomes better than thereception quality of the serving cell.

Specific examples of the combination of measurement report triggeringand the type of a measurement reference component carrier that isincluded in a measurement report by a UE are described below.

(1) As to the event A2, the specific example (2) of the types ofmeasurement reference component carriers is used. This allows thenetwork to recognize that the reception quality of the measurementreference component carrier in the UE becomes worse than a threshold.This enables appropriate component carrier management such as deletionof the measurement reference component carrier from the configuredcomponent carrier. Alternatively, appropriate component carriermanagement can be performed, such as deletion of the measurementreference component carrier from a scheduling component carrier. Stillalternatively, appropriate component carrier management can beperformed, such as deletion of the measurement reference componentcarrier from a candidate component carrier.

(2) As to the event A3, the specific example (2) of the types ofmeasurement reference component carriers is used. This allows thenetwork to recognize that there is a good neighboring cell from thereception quality of the measurement reference component carrier in theUE. This enables appropriate component carrier management such asdeletion of the measurement reference component carrier from theconfigured component carrier and addition of the neighboring cell to theconfigured component carrier, that is, switch of component carriers.Alternatively, appropriate component carrier management can beperformed, such as deletion of the measurement reference componentcarrier from a scheduling component carrier and addition of theneighboring cell to the scheduling component carrier, that is, switch ofcomponent carriers. Still alternatively, appropriate component carriermanagement can be performed, such as deletion of the measurementreference component carrier from a candidate component carrier andaddition of the neighboring cell to the candidate component carrier,that is, switch of component carriers. Yet still alternatively,appropriate mobility management can be performed, such as handover tothe neighboring cell.

(3) As to the event A5, the specific example (2) of the types ofmeasurement reference component carriers is used. Detailed descriptionthereof is similar to that of the event A3, which is omitted.

(4) As to the event B2, the specific example (2) of the types ofmeasurement reference component carriers is used. Detailed descriptionthereof is similar to that of the event A3, which is omitted.

(5) As to the event A3-bis, the specific example (2) of the types ofmeasurement reference component carriers is used. Detailed descriptionthereof is similar to that of the event A3, which is omitted.

FIG. 34 shows an example of the operation. In this operation example,the specific example (5) is used for the type of a measurement referencecomponent carrier. Further, the specific example (2) is used for theinformation of a measurement reference component carrier.

FIG. 35 shows the state of the serving base station and the neighboringbase station. The same reference symbols as those of FIG. 33 denoteequivalent portions, and thus description thereof is omitted.

FIG. 35 shows the case where the reception quality of the 3105neighboring base station_CC_1 becomes better than the reception qualityof the 3301 configured DL_CC_1 and the reception quality of the 3107neighboring base station_CC_3 becomes better than the reception qualityof the 3302 configured DL_CC_2.

FIG. 38 is a block diagram showing a configuration example of the basestation (for example, base station 3308 of FIG. 35 ) according to thepresent embodiment. The same reference symbols as those of FIG. 9 denoteequivalent portions, and thus description thereof is omitted. A controlunit for downlink component A 3801 controls one downlink component. Thecontrol unit for downlink component A 3801 includes a protocolprocessing unit 903-A for downlink component A, a transmission databuffer unit 904-A for downlink component A, an encoding unit 905-A fordownlink component A, a modulating unit 906-A for downlink component Aand a frequency converting unit 907-A for downlink component A.Alternatively, the control unit for downlink component A 3801 mayinclude the protocol processing unit 903-A for downlink component A andthe frequency converting unit 907-A for downlink component A. Stillalternatively, the control unit for downlink component A 3801 mayinclude the control protocol processing unit 903-A for downlinkcomponent A. For example, in a case where the 3301 configured DL_CC_1(f1_DL) is configured as the frequency for downlink component A by thefrequency converting unit 907-A, the control unit for downlink componentA 3801 serves as the control unit for configured DL_CC_1.

A control unit for downlink component B 3802 controls one downlinkcomponent. The control unit for downlink component B 3802 includes aprotocol processing unit 903-B for downlink component B, a transmissiondata buffer unit 904-B for downlink component B, an encoding unit 905-Bfor downlink component B, a modulating unit 906-B for downlink componentB and a frequency converting unit 907-B for downlink component B.Alternatively, the control unit for downlink component B 3802 mayinclude the protocol processing unit 903-B for downlink component A andthe frequency converting unit 907-B for downlink component B. Stillalternatively, the control unit for downlink component B 3802 mayinclude the protocol processing unit 903-B for downlink component B. Forexample, in a case where the 3302 configured DL_CC_2 (f2_DL) isconfigured as the frequency for downlink component B by the frequencyconverting unit 907-B, the control unit for downlink component B 3802serves as the control unit for configured DL_CC_2.

While this configuration example has described the case of two controlunits for downlink component, the case of one or three or more controlunits for downlink component is also conceivable.

A control unit for uplink component C 3803 controls one uplinkcomponent. The control unit for uplink component C 3803 includes aprotocol processing unit 903-C for uplink component C, a decoding unit910 for uplink component C, a demodulating unit 909-C for uplinkcomponent C and a frequency converting unit 907-C for uplink componentC. Alternatively, the control unit for uplink component C 3803 mayinclude the protocol processing unit 903-C for uplink component C andthe frequency converting unit 907-C for uplink component C. Stillalternatively, the control unit for uplink component C 3803 may includethe protocol processing unit 903-C for uplink component C. For example,in a case where the 3306 configured UL_CC_2 (f2_UL) is configured as thefrequency for uplink component C by the frequency converting unit 907-C,the control unit for uplink component C 3803 serves as the control unitfor configured UL_CC_2.

While this configuration example has described the case of one controlunit for uplink component, the case of two or more control units is alsoconceivable.

A protocol processing unit 3804 performs protocol processing of theentire base station. For example, the protocol processing unit 3804performs protocol processing so as to cover the respective control unitsfor components, cover uplink and downlink, or adjust the respectivecomponents.

In Step ST3401, the control unit for configured DL_CC_1 (3301) 3801notifies a UE of the measurement configuration. The measurementconfiguration includes a measurement object, a reporting configuration,and a measurement identity for linking a measurement object with areporting configuration. In this operation example, f1_DL and the PCI ofthe configured DL_CC_1 (3301) are included as a measurement object and ameasurement reference component carrier, respectively. The threshold ofthe event A3 is included as a reporting configuration. A measurement ID“1” is included as the measurement identity. The measurement objectf1_DL is linked with the reporting configuration event A3 by themeasurement ID “1”. Alternatively, the measurement configuration may benotified by means of the frequency layer 3303 (f1_DL). Stillalternatively, the measurement configuration may be notified by means ofthe configured downlink component carrier 1 (configured DL_CC_1) 3301.

In Step ST3402, the UE receives the measurement configuration from thecontrol unit for configured DL_CC_1 (3301) 3801.

In Step ST3403, the control unit for configured DL_CC_2 (3302) 3802notifies the UE of the measurement configuration. The measurementconfiguration includes a measurement object, a reporting configuration,and a measurement identity for linking a measurement object with areporting configuration. In this operation example, f3_DL and the PCI ofthe 3302 configured DL_CC_2 are included as a measurement object and ameasurement reference component carrier, respectively. The threshold ofthe event A3-bis is included as a reporting configuration. A measurementID “1” is included as the measurement identity. The measurement objectf3_DL is linked with the reporting configuration event A3-bis by themeasurement ID “1”. Alternatively, the measurement configuration may benotified by means of the frequency layer 3304 (f2 DL). Stillalternatively, the measurement configuration may be notified by means ofthe configured downlink component carrier 2 (configured DL_CC_2) 3302.

In Step ST3404, the UE receives the measurement configuration from thecontrol unit for configured DL_CC_2 (3302) 3802.

In Step ST3405, the UE performs measurement in accordance with themeasurement configurations received in Step ST3402 and Step ST3404.

In Step ST3406, the UE judges whether or not a trigger has occurred asto the measurement report event transmission, based on the measurementconfigurations received in Step ST3402 and Step ST3404. In thisoperation example, the case where the reception quality of theneighboring base station_CC_1 (3105) becomes better than the receptionquality of the configured DL_CC_1 (3301) is described, and thus the UEjudges that a trigger has occurred as to event A3 transmission. Further,the case where the reception quality of the neighboring basestation_CC_3 (3107) becomes better than the reception quality of theconfigured DL_CC_2 (3302) is described, and thus the UE judges that atrigger has occurred as to event A3-bis transmission.

In Step ST3407, the UE provides a measurement report that the event A3and the event A3-bis have occurred to the base station by means of theconfigured UL_CC_2 (3306). The measurement report is notified to theprotocol processing unit 3804 through the control unit 3803 forconfigured UL_CC_2 (3306). The measurement report includes theinformation of the measurement reference component carrier.Specifically, the measurement report of the event A3 includes the PCI ofthe configured DL_CC_1 (3301), the measurement ID “1” and the PCI of theneighboring base station_CC_1 (3105). The measurement report of theevent A3-bis includes the PCI of the configured DL_CC_2 (3302), themeasurement ID “1” and the PCI of the neighboring base station_CC_3(3107).

In Step ST3408, the protocol processing unit 3804 receives themeasurement report from the UE. The information of the measurementreference component carrier is included per measurement report, andaccordingly the base station can know the measurement referencecomponent carrier per measurement even in a case where asymmetriccarrier aggregation has been performed.

In Step ST3409, the base station 3308 (protocol processing unit 3804)performs handover process based on the measurement report received inStep ST3408.

The fifth embodiment can achieve the following effect.

The network is allowed to recognize the measurement reference componentcarrier even in a case where asymmetric carrier aggregation has beenperformed. This enables to appropriately perform, for example, mobilitymanagement such as handover and component carrier management such asaddition, deletion or switch of component carriers, as a mobilecommunication system. Accordingly, an effect that radio resources areeffectively used can be achieved.

First Modification of Fifth Embodiment

A problem to be solved by a first modification of the fifth embodimentis similar to that of the fifth embodiment, and description thereof isomitted.

A solution in the first modification of the fifth embodiment isdescribed below.

Different portions from those of the fifth embodiment are describedbelow. Portions that are not particularly described are similar to thoseof the fifth embodiment.

In the case of providing a measurement report, the UE notifies theinformation indicating that the RRC message including a measurementreport is the control information corresponding to what downlinkcomponent carrier, with the use of the third solution of the firstembodiment. Further, the UE may include the measurement identity thathas triggered a measurement report to be transmitted, the PCI of aneighboring cell, the measurement results of a serving cell and the likein the measurement report as in the conventional technique. The networkperforms mobility management, component carrier management and the likebased on the measurement report. Specific examples of the entity of thenetwork include a base station.

The UE manages one list of measurement objects, one list of reportingconfigurations and one list of measurement identities per downlinkcomponent carrier where measurement configuration has been performed.This makes it easier for the UE to perform measurement per downlinkcomponent carrier, leading to an effect that the information indicatingthat the RRC message containing a measurement report is the controlinformation corresponding to what downlink component carrier can beadded more easily. Alternatively, the UE may manage a plurality of listsof measurement objects, a plurality of lists of reporting configurationsand a plurality of lists of measurement identities. The “plurality of”may be the number of component carriers that have been configured, thenumber of scheduling component carriers, or the number of candidatecomponent carriers.

Specific examples of the types of measurement reference componentcarriers are similar to those of the fifth embodiment, and thusdescription thereof is omitted.

Specific examples of the information of measurement reference componentcarriers are similar to those of the fifth embodiment, and thusdescription thereof is omitted.

An example of the operation is similar to that of the fifth embodiment,and thus description thereof is omitted.

The first modification of the fifth embodiment can achieve a similareffect to that of the fifth embodiment.

Second Modification of Fifth Embodiment

A problem to be solved by a second modification of the fifth embodimentis similar to that of the fifth embodiment, and thus description thereofis omitted.

A solution in the second modification of the fifth embodiment isdescribed below.

Different portions from those of the fifth embodiment are descriedbelow. Portions that are not particularly described are similar to thoseof the fifth embodiment.

A measurement configuration is made by means of one downlink componentcarrier.

The information on a measurement reference component carrier is newlyprovided to a measurement configuration. There may be a list ofmeasurement reference component carriers. The block (as a specificexample, protocol processing unit 3804 of FIG. 38 ) that adjustsrespective components within a base station or one downlink componentcarrier for configuring a measurement links one measurement referencecomponent carrier and, one measurement object and one reportingconfiguration together by a measurement identity. One block within thebase station or one downlink component carrier performs the linking,which makes it easier to allocate measurement identities without beingoverlapped.

As in the conventional technique, the UE includes the measurementidentity that has triggered a measurement report to be transmitted, thePCI of a neighboring cell and measurement results of a serving cell inthe measurement report. The network performs mobility management,component carrier management and the like based on the measurementreport. Specific examples of the entity of the network include a basestation.

The UE may manage one list of measurement objects, one list of reportingconfigurations, one list of measurement reference component carriers andone list of measurement identities.

The UE may provide a measurement report using an uplink componentcarrier that forms a pair with one downlink component carrier forconfiguring measurement.

Eight specific examples of one downlink component carrier are disclosedbelow. (1) Carrier for notifying a paging message. (2) Carrier fornotifying broadcast information for carrier aggregation or LTE-A system.(3) Carrier for notifying the UE of scheduling results by means of thePDCCH. (4) Downlink frequency carrier in a multicarrier anchor. (5) PCC.(6) Anchor component carrier. (7) Downlink frequency carrier in aspecial cell. (8) Combination of (1) to (7) above.

Specific examples of the information of measurement reference componentcarriers are similar to those of the fifth embodiment, and thusdescription thereof is omitted.

FIG. 36 shows an example of the operation. The same reference symbols asthose of FIG. 34 denote equivalent portions, and thus descriptionthereof is omitted. FIG. 35 shows the state of a serving base stationand a neighboring base station. FIG. 35 shows the case where thereception quality of the neighboring base station_CC_1 (3105) becomesbetter than the reception quality of the configured DL_CC_1 (3301) andthe reception quality of the neighboring base station_CC_3 (3107)becomes better than the reception quality of the configured DL_CC_2(3302). One downlink component carrier for configuring measurement ofthe base station 3308 is denoted by the configured DL_CC_2 (3302). FIG.38 is a block diagram showing the configuration example of the basestation (for example, base station 3308 of FIG. 35 ) according to thepresent embodiment.

In Step ST3601, the protocol processing unit 3804 links one measurementreference component carrier, one measurement object and one reportingconfiguration together. In this operation example, linking is performedin the following two fashions. (1) The configured DL_CC_1 (3301) as ameasurement reference component carrier of the measurement ID “1”, thef1_DL (3303) as a measurement object and the reporting configurationincluding the threshold of the event A3 are linked together. (2) Theconfigured DL_CC_2 (3302) as the measurement reference component carrierof the measurement ID “2”, the f3_DL (3305) as a measurement object andthe reporting configuration including the threshold of the event A3-bisare linked together.

In Step ST3602, the protocol processing unit 3804 notifies the controlunit for the configured DL_CC_2 (3302) 3802 being one downlink componentcarrier that configures measurement of the results of linking performedin Step ST3601 (hereinafter, referred to as “all CC measurementconfigurations”). The all CC measurement configurations may include alist of measurement objects, a list of reporting configurations, a listof measurement reference component carriers and a list of measurementidentities.

In Step ST3603, the control unit for the configured DL_CC_2 (3302) 3802receives the all CC measurement configurations.

In Step ST3604, the control unit for the configured DL_CC_2 (3302) 3802notifies the UE of the all CC measurement configurations received inStep ST3603. The control unit for the configured DL_CC_2 (3302) 3802notifies the measurement configuration targeted for the UE among the allCC measurement configurations received in Step ST3603.

In Step ST3605, the UE provides a measurement report that the event A3and the event A3-bis have occurred to the base station 3308 by means ofthe configured UL_CC_2 (3306). This measurement report is notified tothe protocol processing unit 3804 through the control unit for theconfigured UL_CC_2 (3306) 3803. The measurement report of the event A3includes the measurement ID “1” and the PCI of the neighboring basestation_CC_1 (3105). The measurement report of the event A3-bis includesmeasurement ID “2” and the PCI of the neighboring base station_CC_3(3107). The measurement report is not required to include theinformation of a measurement reference component carrier, leading to aneffect that radio resources are effectively used. In addition, theconventional technique can be used for the measurement report, whichallows a mobile communication system to have high backwardcompatibility.

In Step ST3606, the protocol processing unit 3804 receives themeasurement report from the UE. The measurement identity links onemeasurement reference component carrier, one measurement object and onereporting configuration together, leading to an effect that the networkthat has received the measurement report including the measurementidentity can recognize the measurement reference component carrier.

The second modification of the fifth embodiment can achieve thefollowing effect in addition to the effect of the fifth embodiment.

Differently from the fifth embodiment, additional information is notrequired when a UE transmits a measurement report to a network. Thisachieves an effect that radio resources are used more effectivelycompared with the fifth embodiment. Further, a conventional techniquecan be used for the measurement report, which allows a mobilecommunication system to have high backward compatibility.

Third Modification of Fifth Embodiment

A problem to be solved by a third modification of the fifth embodimentis similar to that of the fifth embodiment, and thus description thereofis omitted.

A solution in the third modification of the fifth embodiment isdescribed below.

Different portions from those of the fifth embodiment are describedbelow. Portions that are not particularly described are similar to thoseof the fifth embodiment.

Measurement is configured for each component carrier.

Adjustment is performed in the base station including a plurality ofdownlink component carriers such that measurement identities are notoverlapped between the downlink component carriers.

The UE allows the measurement report to include the measurement identitythat has triggered a measurement report to be transmitted, the PCI of aneighboring cell and the measurement results of a serving cell, as inthe conventional technique. The network performs mobility management,component carrier management and the like based on the measurementreport. Specific examples of the entity of the network include a basestation.

Nine specific examples of an adjustment entity are disclosed below. (1)Control unit for carrier, which notifies a paging message. (2) Controlunit for carrier, which notifies the broadcast information for carrieraggregation or LTE-A system. (3) Control unit for carrier, whichnotifies the UE of the scheduling results by means of the PDCCH. (4)Control unit for downlink frequency carrier in a multicarrier anchor.(5) Control unit for PCC. (6) Control unit for anchor component carrier.(7) Control unit for downlink frequency carrier in a special cell. (8)New block that adjusts downlink component carriers existing within onebase station, such as the protocol processing unit 3804 of FIG. 38 . (9)Combination of (1) to (8) above.

Three specific examples of adjustment contents are disclosed below. (1)In a case where a new measurement identity is required in a downlinkcomponent carrier, measurement identity allocation is requested for anadjustment entity. The adjustment entity that has received the requestallocates measurement identities such that those are not overlappedbetween a plurality of downlink component carriers. The adjustmententity notifies the downlink component carrier of the allocationresults. A request is made in a case where the measurement identity isnecessary, and thus a margin is not required, leading to an effect of asmaller total number of measurement identities. (2) An adjustment entityallocates in advance measurement identities that can be used by thedownlink component carrier to a plurality of downlink componentcarriers. Allocation is performed in advance, leading to an effect of asmaller control delay. (3) A measurement identity that can be used bythe downlink component carrier are determined in a static manner.

FIG. 37 shows an example of the operation. The same reference symbols asthose of FIG. 34 denote equivalent portions, and thus descriptionthereof is omitted. In this operation example, the specific example (8)is used as an adjustment entity. In this operation example, theadjustment entity is described as the protocol processing unit 3804 ofFIG. 38 . Further, the specific example (1) is used as the adjustmentcontents. FIG. 35 shows the state of a serving base station and aneighboring base station. FIG. 35 shows the case where the receptionquality of the neighboring base station_CC_1 (3105) becomes better thanthe reception quality of the configured DL_CC_1 (3301) and the receptionquality of the neighboring base station_CC_3 (3107) becomes better thanthe reception quality of the neighboring base station_CC_2 (3302). FIG.38 is a block diagram showing the configuration example of a basestation (for example, base station 3308 of FIG. 35 ) according to thepresent embodiment.

In Step ST3701, the control unit for the configured DL_CC_1 (3301) 3801notifies the protocol processing unit 3804 of a measurement identityallocation request.

In Step ST3702, the protocol processing unit 3804 receives themeasurement identity allocation request from the control unit for theconfigured DL_CC_1 (3301) 3801.

In Step ST3703, the control unit for the configured DL_CC_2 (3302) 3802notifies the protocol processing unit 3804 of the measurement identityallocation request.

In Step ST3704, the protocol processing unit 3804 receives themeasurement identity allocation request from the control unit for theconfigured DL_CC_2 (3302) 3802.

In Step ST3705, the protocol processing unit 3804 performs an adjustmentsuch that measurement identities are not overlapped between a pluralityof downlink component carriers, in this operation example, between theconfigured DL_CC_1 (3301) and the configured DL_CC_2 (3302). Forexample, as a result of adjustment, the protocol processing unit 3804allocates the measurement ID “1” in response to the request from thecontrol unit for the configured DL_CC_1 (3301) 3801 and the measurementID “2” in response to the request from the control unit for theconfigured DL_CC_2 (3302) 3802.

In Step ST3706, the protocol processing unit 3804 allocates measurementidentities to the respective control units for downlink componentcarrier that have requested measurement identity allocation. In thisoperation example, the protocol processing unit 3804 notifies thecontrol unit for the configured DL_CC_1 (3301) 3801 of the allocation ofmeasurement ID “1” and notifies the control unit for the configuredDL_CC_2 (3302) 3802 of the allocation of measurement ID “2”.

In Step ST3709, the control unit for the configured DL_CC_1 (3301) 3801notifies the UE of a measurement configuration. The measurementconfiguration includes a measurement object, a reporting configuration,and a measurement identity that links the measurement object with thereporting configuration. In this operation example, the threshold of theevent A3 is included as a measurement configuration, and the measurementID “1” is included as a measurement identity. The measurement ID “1”links the measurement object f1_DL with the reporting configuration ofthe event A3. Alternatively, the measurement configuration may benotified by means of the frequency layer 3303 (f1_DL). Stillalternatively, the measurement configuration may be notified by means ofthe configured downlink component carrier 1 (configured DL_CC_1) 3301.

In Step ST3710, the control unit for the configured DL_CC_2 (3302) 3802notifies a UE of a measurement configuration. The measurementconfiguration includes a measurement object, a reporting configuration,and a measurement identity that links the measurement object with thereporting configuration. In this operation example, the threshold of theevent A3-bis is included as a reporting configuration, and themeasurement ID “2” is included as a measurement identity. Themeasurement ID “2” links measurement object f3_DL with the reportingconfiguration of the event A3-bis. Alternatively, the measurementconfiguration may be notified by means of the frequency layer 3304(f2_DL). Still alternatively, the measurement configuration may benotified by means of the configured downlink component carrier 2(configured DL_CC_2) 3302.

In Step ST3711, the UE performs a measurement in accordance with themeasurement configurations received in Step ST3402 and Step ST3404. Themeasurement reference component carrier may be the downlink componentcarrier where measurement has been configured. The measurement isconfigured by each downlink component carrier, which enables to performthis method. The information of the measurement reference componentcarrier does not need to be included in the measurement configuration,leading to an effect that radio resources are effectively used. Aconventional technique can be used for the measurement configuration,which allows a mobile communication system to have high backwardcompatibility. While, it is also possible to use specific examples ofthe types of measurement reference component carriers of the fifthembodiment.

In Step ST3712, the UE provides a measurement report that the event A3and the event A3-bis have occurred to the base station 3308 by means ofthe configured UL_CC_2 (3306). The measurement report is notified to theprotocol processing unit 3804 through the control unit for theconfigured UL_CC_2 (3306) 3803. The measurement report of the event A3includes the measurement ID “1” and the PCI of the neighboring basestation_CC_1 (3105). The measurement report of the event A3-bis includesthe measurement ID “2” and the PCI of the neighboring base station_CC_3(3107). The information of the measurement reference component carrierdoes not need to be included in the measurement report, leading to aneffect that radio resources are effectively used. Further, aconventional technique can be used for the measurement report, whichallows a mobile communication system to have high backwardcompatibility.

In Step ST3713, the protocol processing unit 3804 receives themeasurement report from the UE. The measurement identities are notoverlapped between a plurality of downlink component carriers, leadingto an effect that the network that has received the measurement reportincluding the measurement identities can recognize the measurementreference component carrier.

The third modification of the fifth embodiment can achieve the followingeffect in addition to the effect of the fifth embodiment.

Differently from the fifth embodiment, additional information is notrequired when measurement is configured from the network to the UE andwhen a measurement configuration is performed from the UE to thenetwork. This achieves an effect that radio resources are used moreeffectively compared with the fifth embodiment. Further, a conventionaltechnique can be used for the measurement report, which allows a mobilecommunication system to have high backward compatibility.

1. (canceled)
 2. A mobile communication system in which, with use ofaggregated carriers including a plurality of component carriersaggregated, a base station performs radio communication with a userequipment corresponding to the aggregated carriers, wherein in a casewhere a new component carrier is added to the aggregated carriers,component carrier information being information of the component carrierto be newly added is transmitted from the base station to the userequipment and control information related to the component carrier to benewly added is transmitted from the base station to the user equipment.3. A base station configured to, with use of aggregated carriersincluding a plurality of component carriers aggregated, perform radiocommunication with a user equipment corresponding to the aggregatedcarriers, wherein in a case where a new component carrier is added tothe aggregated carriers, component carrier information being informationof the component carrier to be newly added is transmitted from the basestation to the user equipment and control information related to thecomponent carrier to be newly added is transmitted from the base stationto the user equipment.
 4. A user equipment configured to, with use ofaggregated carriers including a plurality of component carriersaggregated, perform radio communication with a base station, the userequipment corresponding to the aggregated carriers, wherein in a casewhere a new component carrier is added to the aggregated carriers, theuser equipment receives component carrier information being informationof the component carrier to be newly added from the base station andreceives control information related to the component carrier to benewly added from the base station.